Julian algorithm by Dionysius Exiguus. (A.D. 525)
Valid for any year on the Julian calendar.
The algorithm below is the best I could make of what Dionysius Exiguus described A.D. 525 in his
Liber de Paschate
(here's my Dutch Translation thereof).
The Roman Catholic Church depracated this method, which is now called the Julian method,
and replaced it with the Gregorian method in October 1582
(so the first Gregorian Easter was in 1583).
Not all countries made the switch at the same time, but nowadays all western countries use the Gregorian method,
so the method below will NOT give you this year's correct Easter Date according to the Roman Catholic Church.
Some Eastern European Churches still use the Julian method to compute Easter.




Epact = ( (year MOD 19) x 11) MOD 30 



Paschal_Luna_XIV = 36  Epact 



if Paschal_Luna_XIV < 21 then add 30 to Paschal_Luna_XIV 



Concurrentibus = (year + (year DIV 4) + 4) MOD 7 



if Concurrentibus = 0 then Concurrentibus = 7 



Paschal_Luna_XIV_day = (Paschal_Luna_XIV + Concurrentibus  3) MOD 7 



if Paschal_Luna_XIV_day = 0 then Paschal_Luna_XIV_day = 7 



Easter_Sunday = Paschal_Luna_XIV + 8  Paschal_Luna_XIV_day 

