Astronomical Lunisolar Cycles and Late Antique Chronology

This article advances the hypothesis that the heightened eschatological sensitivity evident among the historians writing in the 5th century and its weaker echos in the time of Charlemagne were caused by the irregularities of the the lunisolar calendar and its particular realization, the Easter calendar. The lunisolar calendar that Christians used for the calculation of the date of the Easter had a number of key periods when the cycles of the Sun and the Moon came in sync in relationship to the beginning of the count and thus produced an effect of the times repeating themselves or ending with the nearly precise astronomical repetition. It is shown that Late Antique scholars who were actively involved in the construction of the Christian history's chronology were limited in their choices by the astronomical peculiarities of the Earth-Moon system. The total conjunctions of the astronomical Solar and Lunar calendars took place, some within the 1st century CE, and the next one, in 483 CE. This was also a special year because the lunar calendar lost one day. Thus the 5th century was the time of heightened expectations of whether the calendar and the Moon's showings will repeat those that accompanied the birth of Jesus. The Full Supermoon (or whatever phase it was on December 25th, 1 BCE) may have repeated in 410 CE (the entry of Goths into Rome), in 467 CE and in 476 CE (the Fall of the Roman Empire), marking the coming of the time very similar to Jesus' birth. The Full Moon was supposed to repeat December 25th, 800 CE and in the year 1000 CE. This may have determined the setting of the biblical calendar in a way that put the birth of Christ on 5199 CE (making the year 800 CE, the year of the Full Supermoon or of its phase on December 25th, 1 BCE) a critical turning point.