Millennium Mistake

© 2003 Jan Zuidhoek 2008

www.millenniummistake.net

 

 

 

 

 

 

1 introduction

The nineteenth turn of century was celebrated exuberantly on 1-1-1901, but the second turn of millennium, which coincided with the twentieth turn of century, on 1-1-2000. There is something wrong there.

If people hear someone asserting that the year 2000 was the last year of the previous millennium then they often react by saying something like: “oh no, the year 2000 was the first year of the new millennium, because the year zero was the first year of our era”. At first sight it possibly looks as if the logic of such a reaction leaves little to be desired, for a millennium is by definition a period of one thousand years. But what is meant by “the year zero”? To be able to answer that question, and with this the tricky question when exactly the third millennium began, we have to find out which is exactly the structure of our era (the term ‘era’ in the meaning of a linear system of numbered calendar years). For that purpose we will enter the field of (general historical) chronology, which, as the science of locating historical events in time, is part of the discipline of history (chronology is the backbone of history).

After having taken note of the history of the coming into existence of our era (in section 2 and section 5) we will establish that there is no year zero in our era (in section 5) and explore why there is no year zero in our era (in section 6). After having established thus which is the connection between the moment zero (i.e. the beginning moment) of our era and the millennium question (see also e.g. www.janzuidhoek.net) the solution of this question (see section 8), as well as the justification of the term ‘millennium mistake’ (see section 10), is there for the taking. Clarifying remarks in reply to the standpoint with regard to the millennium question taken in this website and sceptical reactions to it led to reformulation of passages or have been included among the deductions of section 7 or incorporated into the objections of section 9.

Besides the millennium question still some other subjects related to the beginning of our era (but not being of vital importance for the solution of the millennium question) are treated in this website article, e.g. in section 3 calendars, in section 4 Easter tables, in section 11 Anni Domini. A table obtained at my investigation into Anni Domini provides us not only with the least improbable two dates of Jesus’ dying day (see section 11), but also with a first indication that the replacement of dates of the fourteenth day of Nisan (see section 3) with dates of Alexandrian Paschal full moon (see section 4), which the church of Alexandria (Egypt) implemented about the year 320 to make possible the construction of the first generation of the metonically specific Easter tables (see section 13) so important for the history of Christianity, must have gone hand in hand with rather substantial changes of position with respect to Nisan (not particularly in accordance with the tradition which says that “Paschal full moon = 14 Nisan”), which changes of position are examined more closely in section 12 and are explained in section 13. After an analysis of facts with regard to the total solar eclipse observed in the year 664 in Britain and Ireland which leads to a remarkable conclusion which only can be explained in terms of those changes of position (see section 14) and an account with regard to the consequences of those changes of position (see section 15), this article will be rounded off with an epilogue in which the reasons are summarized why this website exists (see section 16) and a concise profile of the author (see section 17).

This website is provided with an index and a concise bibliography.

 

2 incomplete era

Our era is the complete Christian era (see also section 5), nowadays in combination with the Gregorian calendar (see also section 3) the most widespread dating system on earth. The founder of that era is the erudite monk Dionysius Exiguus, who, originating from a region in or near the Danube delta area, settled in Rome about the year 500. In the year 525 he finished his Easter table (see table 1), which forms a continuation of an Easter table attributed to bishop Kyrillos of Alexandria (in Egypt). The most important detail of Dionysius Exiguus’ Easter table (see also section 4) is that the calendar years (Roman calendar) herein (see column A) are not numbered according to the era of the emperor Diocletianus, as still was the case in the Easter table attributed to Kyrillos, but according to his new era, which was intended to have begun with Jesus’ incarnation.

Now the dating of Jesus’ birth is an impossible task, even for modern historians (see also section 11). So it is not so surprising that Dionysius Exiguus was not able to that either. Be that as it may, he chose indirectly (via the era of the emperor Diocletianus) the Roman year 754, i.e. the year 754 of the Anno Urbis Conditae (literaly ‘in the Year of the Foundation of the City’) era, as the starting year of his new era, on the basis of rational and intuitive considerations (see also section 11). Then he took the successive Roman calendar years from and including that starting year and numbered them 123……. With the duration of a year as unit of time, the incomplete Christian era, better known as Anno Domini (literaly ‘in the Year of the Lord’) era, thus obtained, boils down to our first timeline:

 

                                                                  *   year 1   1   year 2   2   year 3   3 ……… time (in years)

 

in which (modern) picture moment * = the moment zero (i.e. the beginning moment) of our era, i.e. the midnight point in time at which the first day of our era began, and year 1 = the year 1 (of our era) = the Roman year 754 and e.g. year 10 = the year 10 (of our era) = the Roman year 763 (this calendar year began at moment 9 and ended at moment 10). The first day of our era is not the day of Jesus’ birth, but simply 1-1-1.

About a moment zero or about a year zero Dionysius Exiguus, who used no other numerals than Roman ones in his Easter table and in his calculations, never worried. Though he understood very well that dividing (which in this case boiled down to repeated subtraction, for in his time in Europe division algorithms were not available yet) a positive integer by e.g. 19 sometimes produces no remainder, the number zero, being an (extremely important) mathematical concept, was not known to him. That is the reason why in our first timeline (see figure 1) the place of the moment zero of our era has been marked by means of an asterisk (*).

Zero is a name of our tenth digit as well as of the number 0 with the unique property that x + 0 = x for any number x. The digit zero in the (originally Indian) decimal positional system as well as the number zero is usually indicated with the symbol 0. For centuries before the invention of the number zero (see also section 5) precursors of the number zero were used (e.g. in Egypt and in Mesopotamia), i.e. symbols representing an empty spot in a positional system or words representing literally ‘nothing’ which were not considered by their users as (abstract) numbers with which abstract calculations could be carried out actively.

Why must the digit 0 be considered (historically seen) as our tenth digit? Counting precedes calculating, personally as well as (pre)historically. From time immemorial one counts by means of the cardinals one, two, three, …… (in words, and without zero). In order to create a decimal positional system we need nine symbols for the first nine positive integers (e.g. the digits 1, 2, 3, 4, 5, 6, 7, 8, 9) and next a tenth symbol (e.g. the digit 0) to make it possible to compose a symbol (e.g. the symbol 10) for the tenth positive integer. And thus it has gone. Gerbert, the French mathematician who became pope Sylvester II in the year 999, knew of the first nine digits belonging to the decimal positional system, but certainly he did not know the real significance of the digit 0. It is the digit 0 which has enabled us to construct our decimal positional system. As inventing the number zero did not precede the discovery of the positive integers, inventing the digit 0 did not precede the formation of symbols for the first nine positive integers.

The number zero is a relatively modern concept, which could jell only after one had got sufficient experience with the use of its precursors. The last phase of that development was the phase in which one became definitely familiar with carrying out abstract calculations with all ten digits (including the digit zero) in the decimal positional system (this explains that the invention of the number zero happened so long after the discovery of the positive integers). However, in early medieval Europe one used no other numerals than Roman ones and one had to make do, just like in ancient Rome, with abacuslike aids and simple calculations in which neither a numeral zero nor the number zero was used. In that Europe nobody was acquainted with a numeral zero or the number zero. Neverless, the presence of the Latin word “nulla” (meaning ‘none’) in the third column of his Easter table (see table 1) creates the impression that Dionysius Exiguus did know that important number. However, by analyzing the text accompanying his Easter table, we can convince ourselves of the fact that that impression is false (see also section 4).

Of course ‘the year 1’ means simply ‘the first year of our era’, as ‘the king William I’ means nothing else than ‘the first king named William’. For the counting of any kind of things we do not need the number 0 at all. So the counting of years is not different from the counting of any other kind of things (even though sometimes for a moment one could think that the counting of months actually ought to start from the number 0 instead of the number 1, for javascript planners thought to do science a service by assigning in their system the number 0 instead of the number 1 to the first month of the year). So someone born on 1-1-1 will have celebrated his tenth birthday probably (as usual) on the day he completed the tenth year of his life, so on 1-1-11.

Not relevant to the solution of the millennium question but illustrative for the fact that it is absolutely not obvious indeed that in case of the introduction of a new era one begins with a year zero, is the example of the French revolutionary era. When on 22-9-1792 French revolutionaries proclaimed the first French republic they also resolved to begin a new era on this special day; this day was regarded as the first day of the first month of the year 1 of their new era. They also had no need for a year zero, although in France in the course of the eighteenth century the number zero had been generally accepted (see also section 5). Apart from that it is interesting to remark that the introduction of the era of the French revolution, unlike the introduction of the Anno Domini era, was accompanied by a drastic reform of the calendar. Any calendar year of the French revolutionary era began close by the September equinox and consisted of twelve months of thirty days each and five or six single days with which this calendar year was supplemented. The French revolutionary era was in use only to 1-1-1806.

In Roman antiquity calendar years were frequently counted from any supposed year of foundation of the city of Rome. However, in reality the Anno Urbis Conditae era, like the Anno Domini era, did not exist yet in antiquity, for it was used systematically for the first time not before about the year 400, namely, though in a rather careless way, by the Iberian historian Orosius. Though probably Dionysius Exiguus was acquainted with (but never used) the Anno Urbis Conditae era, pope Boniface IV (about the year 600) seems to have been the first who recognized the connection between those two important eras (i.e. AD 1 = AUC 754). However, the complete Christian era (see also section 5) came actively into use as a coherent system for dating historical and current events only in the eighth century. Only in the tenth century our era was used for the first time for the dating of a papal document (namely in the year 967), and only about the year 1060 the church of Rome put this era definitely into use. Never any authority or government or the United Nations did definitely away with our era or replaced this (nowadays generally used) era definitely with another.

The next section being of importance for the solution of the millennium question is section 5.

 

3 calendars

Besides the millennium question still some other subjects related to our era are treated in this article, e.g. in this section calendars, in section 4 easter tables, in section 11 Anni Domini, in section 12 full moons (however, for the solution of the millennium question these subjects are not of vital importance). The next section being of importance for the solution of the millennium question is section 5.

Relatively shortly before he was assassinated, Julius Caesar had modernized the then gradually hopeless outworn Roman calendar, at which he had decreed not only that henceforth every new calendar year should begin on 1 January and once every four years there should be a leap year but moreover that this regulation was considered to apply (retrospectively) to the calendar years gone by. However, in the first half century of its existence the leap year regulation of the Julian calendar did not function well (see also section 7). For that reason the emperor Augustus made (around the beginning of our era) a regulation according to which henceforth every fourth calendar year after the Roman year 757 should be a leap year; this regulation boiled down to the rule that henceforth any calendar year of the Anno Domini era after the year 4 should be a leap year if and only if its number is divisible by 4 (see also section 11). Only in the sixteenth century the Roman calendar was adjusted once again, namely by pope Gregory XIII in the year 1582, which resulted in the (nowadays mondially used) Gregorian calendar equipped with the current leap year regulation (see also section 7). Although the Julian calendar was no ideal calendar, it functioned perfectly and continuously from 5 to 1582. Not surprsingly the dates given in Dionysius Exiguus’ Easter table are Julian calendar dates.

In the first four centuries of our era besides the Julian calendar still an other solar calendar was in general use in the Roman empire, namely the Alexandrian calendar, which like the Julian calendar was equipped of a leap year proportion of one to four. Contrary to those two mutually convertible calendars, the Egyptian calendar (the calendar without leap year regulation of which the Alexandrian calendar was an improved version) was only used for agricultural and astromical purposes. It is a matter of course that with respect to historical events after the year 1582 we normally make use of Gregorian calendar dates and with respect to historical events before the year 1582 we normally make use of Julian calendar dates (which sometimes are Alexandrian calendar dates converted to the Julian calendar).

Unlike the Julian and the Alexandrian calendar, the Jewish calender was (and still is) a lunar calendar. From its coming into being, in Palestine, far before the beginning of our era, to about the year 360 the Jewish calendar, which was used then almost exclusively in Palestine, was not exactly calculable, owing to the fact that the beginning of the new month and of the new year of this calendar depended then not only of astronomical circumstances but also of meteorological ones (in Palestine). Every Jewish calender year consisted then (and still consists now) either of twelve (mostly) or of thirteen Jewish calender months, each of them consisting of 29 or 30 days. At that time Nisan was the first, Iyyar the second and Shebat the eleventh month of the Jewish calendar year and every year early on in spring Passover was prepared in the afternoon of the fourteenth day of Nisan and celebrated at full moon during the evening and the night of the fourteenth to the fifteenth day of Nisan. Nisan always consisted (and still always consists) of thirty days.

In the first century of our era by tradition the beginning of every new month of the Jewish calendar was determined at a very special moment, namely at sunset in Palestine at the beginning of the thirtieth night after the sunset by which the expiring Jewish calender month had begun. Once a month, always at such a special moment, on average about 24 hours after (the actual) Newmoon (point in time of conjunction of sun and moon), a decision had to be taken concerning the beginning of the new Jewish calendar month. If at that special moment visibility of the new crescent was confirmed by the Jewish authorities in Palestine then at that moment the first day of the new Jewish calender month began; otherwise the first day of the new Jewish calender month began at the moment of the then next sunset (hence the Jewish calender months thus defined, consisted of 29 or 30 days each). As it rarely happens that a waxing moon is visible at sunset with the naked eye earlier than 24 hours after Newmoon, in the first century the first day of a new Jewish calender month began usually (but by no means always) with the second sunset in Jerusalem after Newmoon and at the time the (actual) Fullmoon (point in time of opposition of sun and moon) of a Jewish calender month fell on average near the midnight point in time between the thirteenth and the fourteenth day of this Jewish calendar month.

In the first century in Palestine at set times not only a decision had to be taken concerning the beginning of the new month of the Jewish calendar year (once a month) but also a one concerning the beginning of the new year of the Jewish calendar year (once a year). At that time the Jewish authorities there had the competence to interfere once a year, at the end of Shebat, with the current Jewish calendar year by inserting an extra calendar month, existing of thirty days, between the eleventh and the last month of the current Jewish calendar year. In the first century the Jewish authorities in Palestine, though ignorant of any date of the spring equinox (they were familiar then neither with the Julian calendar nor with the Alexandrian one), were able, by plying that competence with due care, not only to prevent that on average the Jewish calendar year should become too short or too long but also that Passover should be celebrated too early (i.e. still in winter). The only not opportunistic criterion therewith was the principle that Passover should be celebrated as early as possible in spring.

After the destruction of Jerusalem in the year 135, too, there were always Jewish communities in Palestine. In the course of the first millennium their number fluctuated greatly, around the third turn of the century their total size numbered probably no more than ten percent of their total size in the first half of the first century. At a particular moment (about the year 360) the jewish calendar was fixed (and thus implicitly related to the Alexandrian and the Julian calendar). Thus in particular all dates of the fourteenth day of Nisan from that moment were fixed. But in the second and the third century and in the fourth century until that moment the beginning of the new month and the beginning of the new year of the Jewish calendar were determined officially still in Palestine and in principle still in the same way as in the first century.

Unlike the Jewish communities in Palestine, the Jewish community in third century Alexandria (Egypt) felt compelled (because it wanted to celebrate its festivities as much as possible at the same time as the Jewish communities in Palestine) to make use of a lunar calendar scheme adjusted to the Alexandrian calendar. That lunar calendar scheme, constructed of course with the help of lunar phase tables, was a system according to which successive time intervals each with a total duration of 19 Alexandrian calendar years were subdivided always in the same way into 235 (in principle consisting of 29 or 30 days) Alexandrian lunations as precisely as possible consonant with Jewish calendar months, resting on the astronomical fact discovered in Mesopotamia as early as in the fifth century before Christ that time intervals of 19 solar calendar years contain on average nearly as many days as a time interval of 235 synodic months (namely about 6940 days). By means of that lunar calendar scheme the Jewish community in third century Alexandria was able to determine the Alexandrian dates of future Jewish festivities in Palestine independently of the Jewish authorities in Palestine (e.g. the next celebration in Palestine of the first day of the Jewich Paschal feast), albeit not accurate to a day. That lunar calendar scheme can certainly have been a source of inspiration for the Alexandrian computists who about the middle of the third century, on behalf of their Easter tables (see also section 4), began to experiment with sequences of dates with a period of 19 years. Those (Christian) computists, just like the (Jewish) producers of that lunar calendar scheme, will necessarily have been aware of the phenomenon of the March equinox, which marks the beginning of spring on the Northern Hemisphere of the earth.

It is not so difficult to persuade oneself of the astronomical fact mentioned in the previous paragraph. The synodic period of the moon is on average approximately 29.53059 days; this implies that the moon is taking about 6939.689 days to pass through all of its phases 235 times. Although the Julian calendar was no ideal calendar, it functioned perfectly and continuously from 5 to 1582. All that time every century lasted 36525 days; so a time interval of 19 calendar years lasted an average of 6939.75 days then.

Around the year 30 the (real) March equinox fell on 23 or on 22 March, around the year 90 on 22 March, around the year 220 on 21 March, around the year 290 on 21 or on 20 March, around the year 350 on 20 March. However, all that time until about the year 350 the date 25 March was considered by the Roman authorities to be the date of the March equinox. The Jewish authorities in Palestine were then, not bounded as they were to Julian or Alexandrian calendar dates of March equinox, intuitively more familiar with the phenomenon of the March equinox than the Roman authorities. According to the Alexandrian astronomer of Greek descent Ptolemy the date of the March equinox in his time (about the year 140) fell on 22 March; and so during the third century the church of Alexandria considered the date 22 March as the date of the March equinox. About the year 270 the Alexandrian scholar Anatolius (who was bishop of Laodicea from the year 268 until his death in the year 282) made an attempt to reconcile the discrepant viewpoints of the churches of Rome and Alexandria with respect to the date of the March equinox by conceiving the moment of the March equinox not as a point in time or as a date but as a time interval consisting of four consecutive dates (22 up to and including 25 March). But about the year 300, under the influence of Eusebius, the historian who became bishop of Caesarea shortly after the year 313, the date which according to the church of Alexandria had to be considered as the date of the March equinox, was reconfirmed on 22 March. However, relatively soon after that the church of Alexandria definitely decided, on the basis of astronomical calculations of around the third turn of century, to consider the date 21 March so familiar to us (in that time and nowadays once again usually the first day after the March equinox). That happened about the year 320; the church of Rome took that step about the middle of the fourth century.

The (unfortunately unknown) lunar calendar scheme the Jewish community in third century Alexandria used, must have been already before the middle of the third century of such a quality that (e.g.) the sequence of dates of the fourteenth day of the Alexandrian lunation of Nisan must have got already something of a metonical structure. A metonically structured sequence of dates is by definition a sequence of dates with a period of 19 years such that every following date of the sequence can be obtained by subtracting either 11 days modulo 30 days (normally) or 12 days modulo 30 days (only in the case of the saltus lunae, once every nineteen times) from the last preceding date. An important example of a metonically structured sequence of dates is the sequence of Julian calendar dates of column F of table 1, of which the metonical core, i.e. the first partition of the sequence consisting of the first nineteen terms of the sequence, covers the time interval consisting of the years 532 up to and including 550 and the first saltus lunae occurs at the transition from 550 to 551. We will work out by means of table 2, which concerns a suitably chosen time interval congruent modulo 19 years with that special time interval, in which way Alexandrian Jewish calculators (possibly as early as about the year 240) ideally (so as to concentrate our thoughts on the least improbable possibility) could have obtained their first metonically structured sequence of dates of the fourteenth day of the Alexandrian lunation of Nisan.

In table 2 (with dates according the Julian calendar) we see for each indicated calendar year (in the primary column A) mentioned in column B the best possible estimated point in time for Jerusalem of the (actual) Newmoon of Nisan, in column C the (most probable) date of the first day of Nisan estimated on the basis of column B (using the fact that in the third century the first day of every new month of the Jewish calendar usually began with the second sunset in Jerusalem after Newmoon), in column D the best possible estimated point in time for Alexandria of the (actual) Fullmoon of Nisan, in column E the date of the fourteenth day of Nisan estimated on the basis of column C, in column F the date of the fourteenth day of the Alexandrian lunation of Nisan estimated on the basis of columns D and E (the dates of column F have been chosen such that the sequence made up by these dates satisfies the requirement of metonical structuredness). In column B always the best possible estimated point in time for Jerusalem of the first Newmoon after 5 March 18:00 has been mentioned; the choice for this utmost point in time is connected with the principle that Passover should be celebrated as early as possible in spring (in column E as well as in column F the earliest date is 21 or 22 March indeed).

Comparing the sequences of dates of columns D, E and F of table 2 with each other, we can verfy that the sequence of dates of column F is a reasonable metonically structured approximation of the sequence of dates of column D as well as of the one of colum E (the saltus lunae occurs at the transition from 243 to 244). Possibly the sequence of dates of column F is the metonical core of the (metonically structured) sequence of dates of the fourteenth day of the Alexandrian lunation of Nisan which was disposed by Jewish calculators in third century Alexandria, in which centre of science of course (though probably not very accurate) lunar phase tables must have been available.

 

4 easter tables

Besides the millennium question still some other subjects related to our era (but not being of vital importance for the solution of the millennium question) are treated in this article, e.g. in section 3 calendars, in this section Easter tables, in section 11 Anni Domini, in section 12 full moons. The next section being of importance for the solution of the millennium question is section 5.

At the first council of Nicaea, convened in the year 325 by the emperor Constantine I, it was decided to adopt the Julian calendar (see section 3) as official calendar of the church and that henceforth Easter Sunday should be celebrated every spring by all Christians in principle on the very same Sunday after the preparation day of Passover (see section 3), which always fell on the fourteenth day of Nisan (see section 3). At that important council one came also to the conclusion that for practical reasons it was necessary to be always amply in advance well informed about dates being eligible for the celebration of Easter Sunday, and that because of the then incalculability of the Jewish calendar (see section 3) accurate Easter tables adjusted to the Julian or to the Alexandrian calendar were required. The bishops who were together in the year 325 in Nicaea, were agreed about that Easter Sunday ought to be celebrated in principle on the first Sunday after “the full moon of Nisan”, but could not agree about how the date of this Sunday had to be calculated.

In the time of the first council of Nicaea some considerable time Easter tables were in use. In the beginning of the third century computists of some churches, among which the church of Rome and the one of Alexandria (Egypt), had gone to calculate their own periodic sequences of dates of Paschal full moon, to be able to determine their own dates of Easter Sunday. To be able to develop those easter tables, owing to the then incalculability of the Jewish calendar (then still always determined in Palestine and used nearly exclusively in Palestine), one had been forced to replace the dates of preparation day of Passover with fixed substitutes (so called dates of Paschal full moon) arranged in periodic sequences, which had usually been adapted to one of the calendars then generally used, namely the Julian calendar, used by the church of Rome, and the Alexandrian calendar (see section 3), which the church of Alexandria mostly used. An important example of a (periodic) sequence of dates of Paschal full moon is the sequence of Julian calendar dates of Alexandrian Paschal full moon which we see in column F of table 1. Obviously periodic sequences of dates of Paschal full moon and (incalculable) sequences of dates of the fourteenth day of Nisan, initially as few different as possible, could in no case entirely tally with each other. During almost five centuries the sequences of dates of Paschal full moon plied by the different churches could show great differences, which was the main cause of the fact that the easter tables propagated by the different churches could be mutually strongly different and by no means always led to the same dates being eligible for the celebration of Easter Sunday.

The lunar calendar scheme which was used by the Jewish community in third century Alexandria (see section 3) can certainly have been a source of inspiration for the Alexandrian computists who around the middle of the third century had been begun to experiment with sequences of dates with a period of 19 years. Anyway, around the year 250 they adopted, on behalf of their Easter tables, the Alexandrian lunations being part of that lunar calendar scheme and the accompanying system of lunar phase numeration, in which e.g. lunar phase number 14 indicated the “age” of the moon (i.e. the lunar phase) on the fourteenth day of every lunation. The lunar phase numbers thus obtained varied from 1 to 29 or 30, where 30 often was replaced with a precursor of the number zero (e.g. “nulla” in Dionysius Exiguus’ Easter table). It is a matter of course that it is not the fourteenth day of Nisan but the fourteenth day of the Alexandrian lunation of Nisan (which lunation might then be on average equal to Nisan but did not always precisely coincide with Nisan) with which Alexandrian computists their Paschal full moon thought to have to identify, and it is for this reason that the “age” of the moon on any date of their Paschal full moon was (and remained) always 14. Nevertheless, the Alexandrian “adjustment of Nisan” to the Alexandrian calendar, i.e. the replacement of dates of the fourteenth day of Nisan with Alexandrian calendar dates of Alexandrian Paschal full moon, would ultimately result (about the year 320) in substantial changes of position with respect to Nisan which would land the date of the Alexandrian Paschal full moon in almost all calendar years between the years 320 and 360 on or near the twelfth, instead of the fourteenth, day of Nisan (see also section 12).

In Alexandria during the seconde half of the third century 22 March, the date which in the third century by the church of Alexandria was considered as the date of the March equinox, functioned as lower limit of the dates of Paschal full moon. The first by name known Alexandrian computist who applied that principle to sequences of dates with a period of 19 years was Anatolius (see section 3). Anatolius’ Easter table, constructed about the year 270, was with its dates of anatolian Paschal full moon adapted to a theoretically interesting but unusual calendar a rather impractical Easter table, and not surprisingly it went relatively rapidly, about the third turn of century, out of use to make way for an Easter table promoted by Eusebius (see section 3) which was based on a sequence of dates of (which I call for convenience) eusebian Paschal full moon which was provided with a metonical structure (see section 3) and must have had 22 March as earliest date. In all probability the (unfortunately unknown) sequence of dates of eusebian Paschal full moon had a precursor in an (unknown as well) metonically structured sequence of dates of (which I call for convenience) preanatolian Paschal full moon (disposed in Alexandria as early as about the year 260). It is plausible that around the year 250 Alexandrian Jewish calculators disposed for the first time a metonically structured sequence of dates of the fourteenth day of the Alexandrian lunation of Nisan (see section 3), and that about the year 260 Alexandrian Christian computists (among them perchance Anatolius before his consecration to bishop), probably in the same way as the one in which those Jewish calculators proceeded, disposed their (metonically structured) sequence of dates of preanatolian Paschal full moon. We will work out by means of table 3, which (like table 2) concerns a suitably chosen time interval congruent modulo 19 years with the special time interval consisting of the years 532 up to and including 550 (see section 3), in which way Alexandrian computists (about the year 260) ideally could have obtained their first sequence of dates of preanatolian Paschal full moon.

In table 3 (with dates according to the Julian calendar) we see for each indicated calendar year (in the primary column A) mentioned in column B the best possible estimated point in time for Jerusalem of the (actual) Newmoon of Nisan, in column C the date of the first day of Nisan estimated on the basis of column B (in just the same way as in section 3), in column D the best possible estimated point in time for Alexandria of the (actual) Fullmoon of Nisan, in column E the date of the fourteenth day of Nisan estimated on the basis of column C, in column F the date of the preanatolian Paschal full moon estimated on the basis of columns D and E (the dates of column F have been chosen such that the sequence made up by these dates satisfies the requirement of metonical structuredness). In column B always the best possible estimated point in time for Jerusalem of the first Newmoon after 7 March 18:00 has been mentioned; the choice for this utmost point in time is connected with the fact that in the third century the church of Alexandria considered 22 March as the date of the March equinox and with the principle that Passover should be celebrated as early as possible in spring (in column E as well as in column F the earliest date is 22 or 23 March indeed).

Comparing the sequences of dates of columns D, E and F of table 3 with each other, we can verfy that the sequence of dates of column F is a reasonable metonically structured approximation of the sequence of dates of column D as well as of the one of colum E (the saltus lunae occurs at the transition from 263 to 264). Possibly the sequence of dates of column F is the metonical core (see section 3) of the sequence of dates of preanatolian Paschal full moon which was disposed by Christian computists in third century Alexandria. We establish little differences between columns F of table 2 and table 3; there is between these two columns only one relevant difference, namely a difference flowing from the opinion the church of Alexandria in the third century had on the date of the March equinox. It is chiefly that difference which justifies the supposition of the historicity of the (metonically structured) sequence of dates of preanatolian Paschal full moon (with 22 or 23 March as the earliest possible date). By the way, in fact the sequence of dates of preanatolian Paschal full moon could have been an entire other sequence of dates than the sequence of dates of the fourteenth day of the Alexandrian lunation of Nisan.

About the year 320 the church of Alexandria decided to consider henceforth 21 March as the date of the March equinox and to choose (at last) definitely for a particular carefully selected sequence of dates of Alexandrian Paschal full moon (with a period of 19 years). It is the sequence of dates of Alexandrian Paschal full moon which forms the backbone of the Alexandrian Easter tables constructed about the year 320; the metonical core of these Easter tables covers the special time interval consisting of the years 304 up to and including 322, and it is the repetitions of this metonical core which are so characteristic for these Easter tables and all Easter tables evolved from them (by extrapolation). The sequence of dates of Alexandrian Paschal full moon which we see in column F of table 1 consists of five of those repetitions. The metonical core of Dionysius Exiguus’ Easter table is the first of those five repetitions and covers the special time interval consisting of the years 532 up to and including 550, which time interval not surprisingly is congruent modulo 19 years with the special time interval consisting of the years 304 up to and including 322.

For the determination of the date of Easter Sunday the church of Alexandria respected since the beginning of the third century the principle that Easter Sunday = the first Sunday after the Paschal full moon. Julian calendar dates of Alexandrian Easter Sunday determined according to that formula we come across in column G of table 1. Unlike the church of Alexandria the church of Rome respected in the third century for the determination of the date of Easter Sunday the principle that Easter Sunday = the first Sunday after the first day after the Paschal full moon. During the third century and around the third turn of the century the earliest possible date of the Roman Paschal full moon was 18 March. The backbone of the Roman Easter tables constructed in the second half of the third century was formed by a particular periodic sequence of dates of Roman Paschal full moon with a period of 84 years, which however corresponded much less to the astronomical reality than the periodic sequence of dates of Alexandrian Paschal full moon which is so characteristic for the Alexandrian Easter tables constructed about and after the year 320. In those Roman Easter tables the date which according to the Roman authorities had to be considered as the date of the March equinox (25 March according to the then Roman authorities) functioned as lower limit of the dates of Roman Easter Sunday.

By the publication of the Alexandrian Easter tables which had been constructed about the year 320, the church of Alexandria was the first church which opted definitely for 21 March as the earliest (and for 18 April as the latest) possible date of the Paschal full moon. That made the church of Alexandria at the same time the first church which opted definitely for 22 March as the earliest (and for 25 April as the latest) possible date of Easter Sunday (because of the Alexandrian formula for the date of Easter Sunday). In the fourth century at the curches in the western half of the Roman empire chiefly Roman Easter tables were in use, at the curches in the eastern half chiefly Alexandrian ones. It is plausible that, under the influence of Eusebius, at the curches in fourth century Palestine (among which the churches of Jerusalem, Jabneh and Caesarea) no other Easter tables than Alexandrian ones were in use.

About the year 410 the Alexandrian monk and computist Annianos accomplished his Easter cycle, i.e. an in principle perpetual Easter table in which not only the sequence of dates of Paschal full moon is periodic but also the sequence of dates of Easter Sunday. Annianos’ Easter cycle was obtained as a result of extrapolation from the Alexandrian Easter tables constructed about the year 320, as was (see section 2), which was compiled about the year 440. The Easter table attributed to Kyrillos, which concerns the years 437 up to and including 531, was intended for use in the western half of the Roman empire and was therefore equipped with Julian instead of with Alexandrian calendar dates (of Paschal full moon and of Easter Sunday). Dionysius Exiguus (see section 2) obtained his Easter table (which concerns the years 532 up to and including 626) by extrapolation from the Easter table attributed to Kyrillos. Because the Alexandrian formula for Easter Sunday holds not only for all Alexandrian Easter tables constructed about the year 320 but also for all easter tables obtained from them by extrapolation, in all these Easter tables the lunar phase number of the date of Easter Sunday is always an integer between 14 en 22.

In Dionysius Exiguus’ Easter table (see table 1) we see for each indicated calendar year (in the primary column A) mentioned in column C the epact (i.e. the Alexandrian lunar phase number of 22 March), in column D the concurrent (i.e. the weekday number of 24 March), in column F the Julian calendar date of the Alexandrian Paschal full moon, in column G the Julian calendar date of the Alexandrian Easter Sunday, in column H the Alexandrian lunar phase number of the Alexandrian Sunday. Columns B and E are not relevant. For each indicated calendar year the date in column F can be obtained by interpreting the epact in column C as a number of days and subtracting this modulo 30 days from the date 5 april. For each calendar year in column A the date in column G can easily be obtained from the number in column D and the date in column F (by means of the Alexandrian formula for the date of Easter Sunday), and the number in column H from the date in column F and the date in coloumn G (because of the fact that the Alexandrian lunar phase number of the Alexandrian Paschal full moon is 14) or from the “number” in column C and the date in column G (because of the fact that the Alexandrian lunar phase number of 22 March is the epact).

In the Alexandrian Easter tables constructed about the year 320 as well as in the Easter tables obtained from them by extrapolation the dates of (Alexandrian) Paschal full moon form a lunar cycle, i.e. a sequence of dates with a metonical structure (see section 3). But in every one of those Easter tables not only the dates of Paschal full moon form a lunar cycle but also the epacts, because these epacts form a sequence with a period of 19 years such that if every epact of the sequence is interpreted as number each following epact of the sequence can be obtained by adding either 11 modulo 30 (normally) or 12 modulo 30 (only in the case of the saltus lunae, once every nineteen times) to the last preceding epact. The fact that the dates of Alexandrian Paschal full moon form a lunar cycle, rests on the fact that time intervals of 19 solar calendar years contain on average nearly as many days as a time interval of 235 synodic months (see section 3). The fact that in Dionysius Exiguus’ Easter table (see table 1) the epacts (see column C) as well as the dates of Paschal full moon (see column F) forms a lunar cycle is the reason of the subdivision of the columns of this table into (five) groups of nineteen calendar years. It is the sequence of dates (of Alexandrian Paschal full moon) of column F which forms the backbone of Dionysius Exiguus’ Easter table; the first saltus lunae of this metonically structured sequence of dates, of which metonical core covers the time interval consisting of the years 532 up to and including 550, occurs at the transition from 550 to 551.

Dionysius Exiguus seems not to have been aware that the concurrents in the fourth column of his Easter table (see table 1) form a solar cycle, i.e. a sequence of numbers with period 28 such that every following number of the sequence can be obtained by adding either 1 modulo 7 (normally) or 2 modulo 7 (once every four times) to the last preceding number. The periodicity of the solar cycle rests on the leap year proportion of one to four and the fact that a week holds seven days. That implies that in the Roman Easter tables constructed in the second half of the third century not only the dates of Paschal full moon had a period of 84 years but also the dates of Easter Sunday; so these Easter tables are Easter cycles. The Easter table of bishop Theophilos of Alexandria, which was constructed around the year 380, was not only the first Alexandrian Easter table which contained Julian instead of Alexandrian calendar dates (of Paschal full moon and of Easter Sunday) but also the first one which was equipped with a special column containing the concurrents of the calendar years in question.

In the year 616 an anonymous extended Dionysius Exiguus’ Easter table to an Easter table concerning the years 532 up to and including 721, and it is this Easter table which about the year 640 was accepted by the church of Rome, which from the third century up till then had given preference to go on using her own, relatively inadequate, Easter tables. In the year 725 the English monk and historian Beda Venerabilis published a new extension of Dionysius Exiguus’ Easter table to an Easter cycle which is essentially a reinvention of Annianos’ Easter cycle. Beda Venerabilis’ Easter cycle and Annianos’ Easter cycle contain essentially just the same dates of Paschal full moon and of Easter Sunday. Like in Annianos’ Easter cycle in Beda Venerabilis’ Easter cycle the concurrents form a solar cycle (with period 28) and the dates of Paschal full moon a lunar cycle (with a period of 19 years), and consequently the dates of Easter Sunday a sequence of dates with a period of 532 years. In the Byzantine empire thanks to Annianos’ Easter cycle at all times the churches were acquainted with the “only correct” date of the next Easter Sunday. It is Beda Venerabilis’ Easter cycle by means of which also the churches in the part of Europe outside the Byzantine empire got that possibility (see also section 13).

The presence of the Latin word ‘nulla’ in the third column of his Easter table creates the impression that Dionysius Exiguus did know the number zero. But it is not difficult for us to convince ourselves (by analyzing the text accompanying his Easter table) that he was no exception to the generally accepted rule that in early medieval Europe nobody knew the number zero (see section 2). There where we say that the epact is 12, he says “duodecim sunt epactae”, which means “there are twelve epacts”; this clearly implies that “XII” in the third column of his Easter table means “12 epacts”. An interesting question is what he means there where he indicates the epact in his Easter table with the Latin word “nulla”, where we would say that the epact is 0. In that case he says “Anno primo, quia non habet epactas lunares, ……”, which means “In the first year, which does not have lunar epacts, ……”. That clearly implies that the meaning of “nulla” in the third column of his Easter table is “no epacts” (which indeed boils down to ‘nothing’). Furthermore he tells us what is the connection between his “nulla” of the calendar year in question and his “18 epacts” of the previous calendar year, by means of something like our calculating modulo 30, where however “30 epacts” is congruent to “no epacts” modulo “30 epacts” (instead of 30 ≡ 0 modulo 30), since for the calendar year in question he establishes “nihil remanet de epactis”, which means “nothing remains from the epacts”. But where people calculate with numbers of epacts the way infants do with numbers of apples we cannot speak yet of ‘being acquainted with the number zero’. There where Dionysius Exiguus sees purely and simply a column of mutually related separate “numbers” of epacts (such as “12 epacts” and “no epacts”), it is our modernized brain which thinks to see a mathematical structure, a sequence of (abstract) nonnegative integers. Dionysius Exiguus had no symbol for ‘zero’ at his disposal which was actively used by him in his calculations. Dionysius Exiguus’ “nulla” in his columns of epacts stands for “no epacts”, not for the number zero. As a consequence, his set of numbers would always be no more than the set of positive integers. But to call an erudite person like Dionysius Exiguus stupid because he did not know the number zero (which some people do) that is really stupid.

There is nothing from which we can deduce that Dionysius Exiguus was acquainted with the number zero. In medieval Europe one had to wait until as late as about the twelfth turn of century before one got dispose of that important number (see also section 5).

 

5 complete era

Dionysius Exiguus (see section 2) presented his Easter table, with his Anno Domini era (see section 2) included in it, to official representatives of pope John I in or shortly after the year 525. However, eventually it would last still a bit more than two centuries before one got round to put that era into use actively as a coherent system for dating historical events. That happened only in the year 731 through Dionysius Exiguus’ great follower Beda Venerabilis (see section 4).

In order to create the possibility of localizing on the new time scale historical events that happened before the beginning of our era as well, of course the (incomplete) Anno Domini era had to be extended to a complete era. For that purpose first the calendar years (Julian calendar) preceding the year 1 were numbered further and further back into the past 123……, which sequence of calendar years then was joined together with the sequence of calendar years 123…… to the complete sequence of calendar years ……321123……, where the year 1 = the year 1 before Christ = the Roman year 753, and e.g. the year 10 = the year 10 before Christ = the Roman year 744. Thanks to Beda Venerabilis the calendar years of our era were divided into calendar years after Christ and calendar years before Christ, which division ultimately boils down to a division into positively numbered and negatively numbered calendar years without the number 0 being allocated to any calendar year.With the duration of a year as unit of time, the complete Christian era thus obtained, boils down to our second timeline:

 

……… -3  year -3  -2  year -2  -1  year -1  0   year 1   1   year 2   2   year 3   3 ……… time (in years)

 

in which (modern) picture moment 0 = the moment zero (see section 2) of our era, and year -1 = the year 1 = the year 1 before Christ and e.g. year -10 = the year 10 = the year 10 before Christ (this calendar year began at moment -10 and ended at moment -9). The running of things at extending the (incomplete) Anno Domini era to the complete Christian era can be roughly summarized in our observation that the year -x (of our era) = the year x = the year x before Christ, where, however, we have to realize that negative numbers became available only in the course of the second millennium.

We observe that our second timeline (see figure 2) looks like a complete linear time scale (with the duration of a year as unit of time) supplemented with the positions of the positive numbered and of the negative numbered calendar years of our era. However, on closer inspection that timeline cannot represent a pure linear time scale, because two calendar years are not always precisely equally long. Usually the difference between the lengths of two calendar years is either nil or one day (see also section 7). For instance, the difference between moment 11 and moment 12 (this difference is 366 days) is not the same as the one between moment 10 and moment 11 (this difference is 365 days). Nevertheless we may interpret our second timeline (provided that the year -x is taken as the year x before Christ) as a simple and as such consistent mathematical model of Beda Venerabilis’ complete era. Likewise our first timeline (see figure 1) is to be interpreted as a simple and as such consistent mathematical model of the (incomplete) Anno Domini era.

What strikes us most (perhaps even is bugging us) in our second timeline is of course that in here there is no room for a year zero. We will still see (in section 6) why our era from the outset to this very day had to do without a year zero, even though the number zero is common property now for a long time. Modern historians who know their job (and of course we take these people serious) really let the year 1 come immediately after the year -1. It is moment 0, the unique point in time from which the calendar years of our era are counted and which is identical with the point in time [1-1-1 00:00] (in modern notation), which marks the direct transition (turn of year) from the year -1 to the year 1, just as it marks the direct transition (turn of century) from the first century before Christ to the first century (after Christ). Just as there is no zeroth century (and no zeroth millennium), there is also no year zero.

Beda Venerabilis calculated (just like Dionysius Exiguus) only with positive integers represented by means of Roman numerals (these are the letters i, v, x, l, c, d and m of the Latin alphabet). He did not feel the slightest need for a numeral zero; e.g. the sum of cc = 200 and i = 1 was noted in Roman numerals simply as cci. And division algorithms were not available yet in early medieval Europe; in this Europe division boiled down to repeated subtraction. There where Beda Venerabilis in his important book “De Temporum Ratione” about “reckoning of time” explains dividing 725 by 19 he says first that 19 times 30 makes 570 and that 19 times 8 makes 152 and then “remanent iii”, meaning that the remainder is 3. But he refrains from naming the number zero to tell us which remainder one obtains when dividing 910 by 7, for answering this question he says, after having noted that 7 times 100 makes 700 and that 7 times 30 makes 210, simply “nihil remanet” or the equivalent “non remanet aliquid”, meaning “there is nothing left over”. Calculating, he never uses any symbol or word for ‘zero’. And there where he enumerates Greek numerals, he does not observe that there is among them no symbol or word for some numeral zero. There is nothing from which we can deduce that Dionysius Exiguus was acquainted with a numeral zero or with the number zero (see section 4); the same holds for Beda Venerabilis.

In the standard work about “De Temporum Ratione” written by the Canadian historian Faith Wallis we find a modern version of Beda Venerabilis’ Easter cycle (see section 4), with our modern digits and with epacts (see section 4) being 0 once every nineteen years (and even mentioning the year -1). But in original manuscripts written by Beda Venerabilis himself you will find no nonpositive numbers at all and you will see only the Latin word ‘nihil’ (meaning nothing but ‘nothing’) or the Latin word ‘nullae’ (meaning nothing but ‘none’) on the places where we would expect to meet the number 0. For our modern brain it is difficult to interprete “de octaua decima in nullam facere saltum” else than as “to make a jump from 18 to 0”. But even modern people use phrases such as “jump into nothingness”. It is our modernized brain which tries to hoax us into believing to see the number zero there where by early medieval scholars simply ‘nothing’ or ‘none’ was meant. There where Beda Venerabilis calculates with (abstract) positive integers, as soon as the number zero comes into sight (i.e. enters our field of vision) he lapses, just like Dionysius Exiguus, into a less abstract terminology. Dionysius Exiguus’ “nulla” and Beda Venerabilis’ “nullae” in their columns of epacts are typical examples of precursors of the number zero, they stand for “no epacts”, which boils down to ‘nothing’ indeed; but the term ‘nothing’ is, in contrast to the number zero, no mathematical concept. For Dionysius Exiguus and Beda Venerabilis as well as for us ‘adding nothing’ boils down to ‘doing nothing’. But to be able to conceive refraining from any action (‘adding nothing’) as a special case of adding something (‘adding zero’) it takes more than skill in carrying out calculations with positive integers.

Beda Venerabilis like Dionysius Exiguus knew no other numbers than positive ones, just like everyone in first millennium Europe. Even Boetius (around the year 500), the only important mathematician in early medieval Europe, and Gerbert (see section 2) were anything but familiar with the number zero. Nowhere in European literature come down to us from the first millennium the number zero itself can be found. So there is no reason at all to abandon the current opinion that the number zero was unknown in early medieval Europe. So the opinion that Dionysius Exiguus en Beda Venerabilis should be acquainted with the number zero remains really without any rational basis. They were great scholars and skilled computists, but no mathematicians (and even less astronomers). One does not need to be a mathematician to be able, starting from the periodic sequence of Julian calendar dates of Alexandrian Paschal full moon (see section 4) and making use of the leap year regulation of the Julian calendar (see section 3) and the Alexandrian formula for the date of Easter Sunday (see section 4), to determine all Julian calendar dates of Alexandrian Easter Sunday. And when you want to do that with the help of Dionysius Exiguus’ Easter table then you can restrict yourself to the use of columns ADF of table 1.

Ptolemy (see section 3) handled a symbol for a numeral zero in the (originally Babylonian) sexagesimal positional system. But that symbol was not actively used by him as a numeral zero with respect to the Greek numerals (these are the 24 letters of the Greek alphabet supplemented with the obsolete Greek letters digamma, koppa and sampi) he used in his calculations; e.g. the sum of s = 200 and a = 1 was noted in Greek numerals simply as sa. Only after a long maturing process the number zero was discovered in India, where in the sixth century for the first time in our history the symbol o was used in abstract calculations in which it acts the part of neutral element with respect to addition (i.e. x + o = x for any number x). It was the great Indian mathematician Brahmagupta who (about the year 630) was the first who not only used the digit zero in his calculations but also made explicit the most important properties of the number zero. The dissemination of that utmost important number (without the number zero there is no modern mathematics, without modern mathematics no modern engineering) across Asia as well as the one across Europe, which began six centuries later, took centuries. Fibonacci (the Italian mathematician whose important book “Liber Abaci” was finished in the year 1202) was the first European, Robert Recorde (whose important book “Ground of Artes” was finished in the year 1543) the first Briton, Simon Stevin (whose important book “De Thiende” was finished in the year 1585) the first Dutchman who was familiar with the digit zero in the (originally Indian) decimal positional system as well as with the number zero.

If only because of the fact that in the early middle ages the number zero and the negative integers still were completely unknown in Europe, Dionysius Exiguus and Beda Venerabilis could not possibly have understood our second timeline. Dionysius Exiguus did not worry about that, because he did not at all need those nonpositive numbers for the setting up of his incomplete era (which actually was used by him only for the benefit of his easter table), and Beda Venerabilis too could manage very well without these numbers. The complete Christian era was brought into use as a coherent system for dating historical events by Beda Venerabilis in the year 731, and was used by the church of Rome in the tenth century for the first time (see section 2). But the modern concept of the bilateral linear time scale, necessary to be able to understand our second timeline, only could make its entry after people in Europe had got dispose of the number zero (around the year 1200) and of the negative numbers (around the year 1500). The nonpositive integers began to be common property only in the first half of the eighteenth century by the invention of the thermometer (with its bilateral linear calibration).

In times of scarcity of reliable historical factual material the dating of historical events was no simple matter. So by Beda Venerabilis the coming into power of the emperor Diocletianus (which took place in the year 284 but still had been dated by Orosius in the Roman year 1041) was dated in the year 286, the capture of Rome by Visigothic troops (which took place in the year 410) was dated in the year 409, and the death of pope Gregory I (who starved in the year 604) was dated in the year 605. Beda Venerabilis was the first medieval historian who, making use of the complete Christian era, ventured to date the first landing of Julius Caesar in Britain. That military action, which took place in the year -55, was dated by Beda Venerabilis in the year 60 before Christ.

 

6 argumentation

If we have a look to our second timeline (see figure 2) just a bit longer and abstract from the fact that two calendar years are not always precisely equally long then we observe that our era, i.e. the complete christian era (taken as a linear system of numbered calendar years), is bilateraly symmetrical with respect to moment 0, the unique point in time which is identical with [1-1-1 00:00]. That symmetry is rather obvious, we think, as we take it for granted that every century consists of one hundred years (as every kilometre contains thousand metres), and that every (positively or negatively numbered) calendar year of our era belongs to exactly one (positive or negative) numbered century of our era (e.g. the year -100 does not belong to both the first and the second century before Christ). Consequently, in our era there simply cannot be a year zero (provided that we want to preserve symmetry). For such a year zero would have to belong to the first century before or to the one after Christ, but then also (due to the symmetry) both to the first century before and to the one after Christ; but this is incompatible with the principle that every calendar year of our era belongs to exactly one numbered century of our era.

Our era is a bilaterally symmetrical era with no year zero. Both an alternative era with the year 1 as a year zero and a one with the year -1 as a year zero (fundamentally there are no other possibilities to be taken into consideration seriously) are necessarily not symmetrical with respect to moment 0. For that reason none of those alternative eras became common property, though sometimes a variant of the latter one is used by astronomers on behalf of the dating of eclipses. That (nonsymmetrical) variant is the astronomical era, i.e. the era connected with the Julian dating system (not to be confused with the Julian calendar), which shortly after the introduction of the Gregorian calendar was proposed (in the year 1583) by Joseph Scaliger. That dating system was used for the first time in the first half of the eighteenth century (by French astronomers). With the duration of a year as unit of time the astronomical era boils down to our third timeline:

 

……… -3  year -2  -2  year -1  -1  year 0   0   year 1   1   year 2   2   year 3   3 ……… time (in years)

 

in which (modern) picture moment 0 is not identical with [1-1-1 00:00] and year 0 is not exactly equal to the year -1 (of our era). The fact is, the year -1 (of our era) began two days later and ended one day later than the year zero of the astronomical era owing to the initially poor functioning of the leap year regulation of the Julian calendar (see also section 7).

It is just as well that Dionysius Exiguus’ followers did not saddle our (certainly for historians ideal) era with some year zero, for when push comes to shove, everybody prefers symmetry. Not surprisingly astronomers never proposed seriously to replace our bilaterally symmetrical era with their astronomical era (which had been brought into use only for practical reasons). The absence of a year zero in our era is not in the least a mistake of Dionysius Exiguus and his followers; it is purely and simply a condition our era has to satisfy in order to preserve its bilateral symmetry. We can but we do not have to be sad about the absence of a year zero in our era; it is such a thing as the absence of “the king William zero” in a company of kings named William.

The next section being of importance for the solution of the millennium question is section 8.

 

7 deductions

The fact that in the complete Christian era no year zero exists, has farreaching consequences, e.g. that the first decade (after Christ) can be nothing but the time interval consisting of the years 1 up to and including 10 and the first decade before Christ nothing but the time interval consisting of the years -10 up to and including -1; these two decades are separated not by means of a year zero but by means of a point in time, namely moment 0 (see section 5).

Any person born in the year 1 must have been conceived in the year -1 or at moment 0 or in the year 1. And someone born in the year -1 will have celebrated his tenth birthday preferably on the day it was ten years ago that he was born, so in the year 10, and this seems to be (but is not) inconsistent with the mathematical fact that -1 + 10 = 9.

From (inclusive) the year -776 up to and including the year 389 the officially recognized ancient Olympic games were held at Olympia every four years. It is easy to check that the Olympic games of the year -4 were succeeded by those of the year 1.

The Julian calendar (see section 3) was introduced in the year -46, which was accompanied by a single lengthening of the calendar year (Roman calendar) of eighty days, which lenghening (by means of which was effected that the March equinox was in fact put to 23 March), however, was neutralized immediately by the provision that the rule that a calendar year consists of 365 or 366 days was considered to hold not only for future calendar years but for all calendar years, including the calendar year in which the Julian calendar was introduced and (retrospectively) all calendar years gone by.

Unfortunately, in the first half century after Julius Caesar had died (in the year -44) the leap year regulation of the Julian calendar did not function well. The fact is, after the leap year -45 there was until the year -8 by mistake a leap year every three years (instead of every four years). That implies that between the leap years -45 and -9 there were three leap years too much, namely eleven instead of eight. The regulation made for that reason by the emperor Augustus (see section 3), according to which every fourth calendar year after which boils down to the Roman year 757 should be a leap year, effected in addition that none (instead of three) of the fifteen calendar years between the leap years -9 and 8 was a leap year.

In the year 325 the Julian calendar was adopted as official calendar of the church (see section 4). However, the leap year regulation of the Julian calendar was not accurate enough to be suitable to be used just like that indefinitely (for instance around the year 1500 the March equinox fell in reality on 11 March). For that reason the Julian calendar was replaced with the Gregorian calendar. That happened in the year 1582 through pope Gregory XIII. He ordered ten days to be dropped from the tenth month of that year (resulting in the fact that [4-10-1582 24:00] = [15-10-1582 00:00]) and decreed that any calendar year of our era after that year should be a leap year if and only if its calendar year number is divisible by 4 but not by 100 unless by 400. We establish that the year 1582 comprised only 355 days, and so it is the only exception on the rule that a calendar year of the Christian era consists of 365 or 366 days. The leap year regulation of the Gregorian calendar has been brought into force in that year for an indefinite (future) time, and for the time being it will not be necessary to adjust it (once every approximately 3300 years an adjustment the size of one day will be needed). Thus all leap years of the complete Christian era (with its proleptic Julian leap year regulation for all its calendar years before the year 1582 and its nonproleptic Gregorian leap year regulation for all its calendar years after the year 1582) from the far past until far into the future (about the year 5000) have been fixed. However, with regard to that far past we have to realize that in the time after the last past glacial period only since the twelfth century before Christ the March equinox falls in March.

It is in combination with the Gregorian calendar that the complete Christian era has been the most widespread dating system on earth. That era was never abolished or replaced with the astronomical era (see section 6), which is a variant of an alternative era with the year -1 as a year zero, as in our third time line (see figure 3). The astronomical era was complemented not with a Gregorian leap year regulation holding for the whole alternative numbering, but with the (proleptic) Julian leap year regulation holding for all calendar years before the year 1582 and the (nonproleptic) Gregorian leap year regulation holding for all calendar years after the year 1582. Because by definition the year 1582 of the astronomical era and the year 1582 (of our era) are identical, the astronomical era and the Christian one coincide exactly where it concerns the calendar years after the year 4. That implies that a choice for the astronomical era instead of for the complete Christian era would not have led to an other point in time of the second turn of millennium than [1-1-2001 00:00] (see also section 8).

Because the year 4 of the astronomical era was a leap year but the year 4 (of our era) did not, the year 1 of the astronomical era did not begin at [1-1-1 00:00] but began one day earlier, namely at [31-12--1 00:00]. And because the year zero of the astronomical era was a leap year but the year -1 (of our era) did not, the year zero of the astronomical era began two days earlier than the year -1 (of our era), namely at [30-12--2 00:00]. Apparently the year zero of the astronomical era is not exactly equal to the year -1 (of our era). By the way, it is not difficult to check that the leap year -44 of the astronomical era = (exactly) the leap year -45 (of our era).

According to the Roman historian Titus Livius, who lived around the beginning of our era, Rome was founded in the Roman year 1. That calendar year is the first year of the Anno Urbis Conditae era (see section 2). Should Rome indeed be founded in that calendar year then this important historical event will be three thousand years ago not in the year 2247 but in the year 2248 (I am just saying it meanwhile), because the Roman year 1 = the year -753 (of our era). Anyway, the 800th anniversary of the foundation of Rome was celebrated exuberantly in the year 47, the 1000th one in the year 248. However, according to modern historians, Rome was founded only somewhere in the seventh century before Christ.

 

8 conclusion

As soon as we have given account of the fact that our era is quite all right (see section 6) and that 1-1-1 is the first day of our era (see section 2), the millennium question can be settled rapidly and definitely.

Someone born on 1-1-1 will have celebrated his tenth birthday preferably on 1-1-11 (see section 2); and likewise he would, if all was well, have celebrated his 1000th birthday preferably on 1-1-1001, and his 2000th birthday preferably on 1-1-2001. By analogy with that we recognize that, because every millennium consists by definition of one thousand years, the second millennium began on 1-1-1000, and the third millennium on 1-1-2001.

Millennium mistake 1 was made by medieval people who thought that the world would perish on 1-1-1000; what these people did not realise was that on that very day only 999 years of the first millennium had passed. However, the first turn of millennium took place one year later, namely at [31-12-1000 24:00] = moment 1000 = [1-1-1001 00:00].

Millennium mistake 2 was made by modern people who had been fooled by commerce and media and authorities that also did not know any better (and by many a historian who had completely forgotten for a while that our era has no year zero) into believing that, rather than the “dull” date 1-1-2001, the “magic” date 1-1-2000 (with its millennium problem and its millennium madness) had to be the first day of the new millennium. However, the second turn of millennium took place one year later, namely at [31-12-2000 24:00] = moment 2000 = [1-1-2001 00:00].

Because moment 0 = [1-1-1 00:00] the year 1 is the starting year of our era, and so it is the opening year of the first century and of the first millennium. It is not difficult to check that the year 2000 is the last year of the last decade of the last century of the second millennium and that the year 2001 is the first year of the first decade of the first century of the third millennium. The “magic” year 2000 is the closing year of the previous millennium and of the previous century, the “dull” year 2001 is the opening year of the new millennium and of the new century. And of course the year 3000 is the closing year of the third millennium (just as the year 300 is the closing year of the third century and the year 30 the closing year of the third decade).

Because it is not the year zero but the year 1 of the astronomical era (see section 6) which is the starting year (i.e. the calendar year which opens with the moment 0) of this era, replacement of the complete Christian era with the astronomical era would not have led to a point in time of the second turn of millennium different from [1-1-2001 00:00]; for the moments 2000 of these two eras are exactly equal (though their moments 0 differ one day). A choice for an alternative era with the year 1 (of our era) instead of with the year -1 (of our era) as a year zero indeed would have yielded a moment 2000 coinciding with the turn of year with which the year 2000 of this alternative era began; evidently also this interesting turn of year would have been identical with [1-1-2001 00:00].

 

9 objections

“All that is very well” someone still objects, “but after all the twentieth century does consist exactly of those calendar years of our era whose numbers start from 19? This implies that the year 1999 is the last year of the twentieth century!”. The calendar years of our era whose numbers end in 00 throw a spanner into the works. There is no year zero in our era (see section 5); it follows that the year 100 is the last (closing) year of the first century, that the year 200 is the last (closing) year of the second century, that the year 300 is the last (closing) year of the third century, and so on. So the year 1600 is the last (closing) year of the sixteenth century. On closer inspection the apparantly interesting standpoint of Maarten Prak of the university of Utrecht that the battle of Nieuwpoort (which took place in the year 1600) is one of the rare real battles the army of the Dutch republic fought out in the seventeenth century, turns out to be something like the remark that New Year’s Eve is one of the rare really cosy days of the month of January.

“All that is very well” someone still objects, “but who is really mistaken? After all, the nineties of the twentieth century had passed on 1-1-2000!”. Indeed that is true, but the last decade of the twentieth century had begun only on 1-1-1991, and so it had passed only on 1-1-2001. Likewise the book with the pretentious title “The complete History of the twentieth Century”, rashly (just before 1-1-2000) printed in a very big edition, which finishes off with the treatment of the nineties of the twentieth century, is no complete history of the twentieth century, because what happened in the last year of the twentieth century is not in there.

“All that is very well” someone still objects, “but what about my odometer? After I have driven exactly 1000 kilometers, it clearly shows three zeros!”. That is right, but what we state here is not a similarity, but it is just a difference between era and odometer, because of the fact that during its first kilometer the odometer indicates 0000, not 0001. It is true, there is a similarity between odometer and age (so during its twentieth kilometer the odometer indicates 0019, and during the twentieth year of your life you are nineteen years of age), but this is beside the point.

“All that is very well” someone still objects, “but when numbering the floors of a building surely it is logical and common practice to name the first floor floor 1, the ground floor floor 0, and the successive basements floor -1, floor -2, floor -3, ……? When numbering the calendar years of our era we cannot do without the number 0 either!”. We are able to do without a year zero very well (see section 6). Because when numbering the floors of a building sometimes floors are taken not as spaces but as horizontal dividing planes between spaces sometimes the numbering of floors does not correspond to the numbering of the calendar years but it corresponds to the one of the turns of year of our era, as in our second timeline (see figure 2).

“All that is very well” someone still objects, “but what does it matter? After all, the beginning of our era was only chosen at a venture!”. The beginning of our era is moment 0, the unique point in time from which the calendar years of our era are counted and which is identical with [1-1-1 00:00]. In the year 1582 for an indefinite time the number of days of any calendar year of our era was fixed (see section 7). That makes all turns of year, turns of decade, turns of century and turns of millennium of our era fixed for an indefinite time.

“All that is very well” someone still objects, “but what does it matter? After all, it is completely unknown when Jesus was born!”. It is not the (indeed unknown) date of Jesus’ birth that matters for the solution of the millennium question, but it is the first day of the Anno Domini era, i.e. 1-1-1, that is essential here (see section 8). Strictly speaking “the first century before Christ” is not “the last century before the birth of Jesus”, but “the last century preceding 1-1-1”.

“All that is very well” someone still objects, “but surely the millennium question can be solved much more simply? Because there exists no year zero the supposition of a turn of millennium at [1-1-2000 00:00] leads to the absurd conclusion that the first decade consisted of nine years (so the tenth birthday of someone born on 1-1-1 coincided officially with his ninth birthday)!”. That reasoning is correct and leads to the observation that the supposition of a turn of millennium at [1-1-2000 00:00] cannot be part of a consistent system. So that supposition is (scientifically) untenable. But the solution of the millennium question still requires a proof of the fact that our era is quite all right (see section 6<