Of Two Calendars

June 25, 2007 · Posted in Calendar, history · Comment 

At the time at which Julius Caesar took power in Rome, the Roman calendar was already out of date (pardon the pun) because it was not keeping time accurately.  The Julian reform lengthened the months (except February, owing to its religious significance) and provided for an intercalary day to be added every four years to February, creating a leap year. This produced a noticeably more accurate calendar, but it was based on the calculation of a year as 365 days and 6 hours (365.25 d). In fact, the year is 11 minutes and 14 seconds less than that. This had the effect of adding three-quarters of an hour to a year, and the effect accumulated. By the 16th century, the vernal equinox fell on March 10 and caused problems in computing the date of Easter.   Read Full Article