2014-08-24 Julian Calendar In 45 B.C. the Roman world began using the the Julian Calendar, 365.25 days. A leap year every 4 years takes care of the extra 1/4 day per year. A solar year is actually 20 minutes shorter so the Julian Calendar gains 3 days every 400 years. New Year's Day - March 25th In 525 A.D., Dionysius Exiguus introduced the "Anno Domini" calendar system and assigned March 25th as New Year's Day. March 25th is called Annunciation Day after the Feast of the Annunciation when Gabriel told the Virgin Mary she would be the mother of Christ. It is called Lady Day by the British. Gregorian Calendar & New Year's Day - January 1st In 1582, Pope Gregory XIII fixed both problems, the lagging dates and the extra 20 minutes per year. His calendar is called the Gregorian Calendar. Calendar Act of 1750 (Chesterfield's Act) From the 12th century to 1752, the civil or legal year in England began on 25 March. It wasn't until The Calendar Act of 1750 that the British government officially accepted the new calendar. There was a difference of 12 days between the Old Calendar and the Gregorian Calendar. The 25th of March in the Julian calendar was the 6th of April in the Gregorian calendar, and 6 April is still the first day of the fiscal year in the United Kingdom. Old Style / New Style - dual dating The British colonies changed from Julian to Gregorian Calendar at midnight on Wednesday, 2 September 1752; the next day was Thursday, 14 September 1752. Between 1582 and 1752, British and American dates are sometimes expressed in what's called "Old Style (O.S.), "New Style" (N.S.) or "dual dating" as in 1607/8. This accounts for dates between January 1st and March 25th of the year in question. Sources: Wikipedia articles for Julian calendar, Gregorian calendar, Feast of the Annunciation, Old Style and New Style dates, Dual dating, and Calendar (New Style) Act 1750. See also http://www.usgenweb.org/research/calendar.shtml and articles on websites such as Ancestry.com. ~ Ron.V