As you may know, there was a switch in the Western world from the Julian calendar to the Gregorian calendar that the vast majority of us use today. “The motivation for the reform was to bring the date for the celebration of Easter to the time of the year in which the First Council of Nicaea had agreed upon in 325. Because the spring equinox was tied to the celebration of Easter, the Roman Catholic Church considered this steady movement in the date of the equinox undesirable… Between AD 325… (when… the vernal equinox occurred approximately 21 March), and the time of Pope Gregory’s bull in 1582, the vernal equinox had moved backward in the calendar, until it was occurring on about 11 March, 10 days earlier.”
The fix was to make years that are exactly divisible by 100 Continue reading Couldn't Pope Gregory have fixed that OTHER calendar problem?