Dionysius Exiguus' Easter table

Dionysius Exiguus' Easter table is the Easter table (table for determining the date of Easter Sunday ) that around the year 520 by Dionysius Exiguus was constructed. He obtained his Easter table (relating to the years 532 to 626) by using an Easter table attributed to Patriarch Kyrillos of Alexandria . Which to Kyrillos attributed Easter table (relating to the years 437 to 531) was around the year 440 obtained by an extrapolation from around the year 300 constructed Alexandrian Easter table Easter table obtained at the Julian calendar to match. Dionysius Exiguus, in turn, obtained his Easter table by extrapolation from the Easter table attributed to Kyrillos. The great historical importance of Dionysius Exiguus' Easter table is twofold: In fact Dionysius went as follows: He appointed twelve lunar months to 354 days and a solar year of 365 days. That difference of 11 days, meaning that if it is new moon in a given year on January 1, the moon on January 1 of the next year is 11 days old. The following year, 22 days, and the year after 3 days (33 min the lunar cycle of 30), then 14, etc. After 19 years (and one day, but that did Dionysius at the end of the cycle path), it is on 1 January new moon. Because it was the year 532 Dionysius important was divisible by 19, and he saw that if the year is divisible by 19, it is new moon on January 1. To find the age of the moon in each year (the Epact ) is therefore easy to find. Part the first year by 19, take the rest of that division and count on one at that. This number is called (since the thirteenth century), the golden number . With a number from 1 guilder hear Epact of 11; a golden number 2 a Epact of 22. If the phase of the moon on January 1st is known, Dionysius could of course calculate for March 21, and so the next full moon. (He now applied some corrections to keep the moon calculated in step with the astronomical moon .
 * 1) this Easter table could eventually Venerable Bede 'Easter cycle be developed to enable all future Julian dates (ie dates of the Julian calendar) on Easter Sunday could be definitively established (as in column G of Dionysius' table);
 * 2) with his Easter table Dionysius Exiguus in passing introduced the Christian era (see column A of Dionysius' table referenced in the external link), which two centuries later by the Venerable Bede would be used as a coherent system for dating historical events and would eventually become the only current global in-service era.

The first Sunday of the year Dionysius found a similar calculation. Sundays in the Julian calendar have a cycle of 28 years. Since 52 weeks, 364 days a year 365, the first Sunday of January for a day moves backwards (in leap years and two at a time). After 28 years, the cycle is complete. Since January 1 532 was a Thursday, the rule states that if a year is divisible by 28, January 3 is a Sunday. Taking into account leap Dionysius could count so on. His whole system, however, was mixed up in 1582 because of the calendar reform of Pope Gregory XIII

In the Europe of the early Middle Ages, no one knew the number or the number zero . Nevertheless awakens the presence of the Latin word 'nulla' in the third column of his Easter table (see external link) the impression that Dionysius Exiguus that significant number should have known. However, there is nothing which we could infer that. One had in medieval Europe to the second millennium wait before one was made ​​available to the number zero.

[Sources edit ]
Georges Declercq, Anno Domini: The Origins of the Christian Era (Turnhout, 2000)