Most people believe that the year 2000...

Most people believe that the year 2000 is the first year of the new millennium since the numbers go from 1900s to 2000s. Those who “know” better insist that the new millennium begins in 2001.

* Today’s calendar dates back to Pope Gregory XIII in 1582. It replaced the Julian calendar, compiled by the astronomer Sosigenes and instituted in 45 BC by Julius Caesar. Sosigenes’ calendar, however, overestimated the length of the year by about 11 minutes. Not very much. But by 1582, the Julian calendar had become 10 days out of sync with the solar cycle. Ten days were dropped. Thursday Oct. 4, 1582, was the last day of the Julian calendar and the next day, Friday, Oct. 15, was the first day of the Gregorian calendar.

* Throughout history, New Year’s Day was celebrated on different dates by different peoples. When England and its colonies finally adopted the new calendar in 1752, they had to drop 11 days and designated Jan. 1 as New Year’s Day. Prior to this, the new year was commonly celebrated on March 25 in the American Colonies. Contemporaneously, George Washington’s birth date moved from Feb. 11, 1731, on the Julian calendar to Feb. 22, 1732, on the Gregorian.

* The Christian era system of numbering years was instituted in the year AD 525 (Anno Domini or Year of the Lord). A Roman scholar, Dionysius Exiguus, adopted the birth of Jesus as the initial epoch for his calendar. Unfortunately, not only was his estimate of the year of Jesus’ birth off by about five years, his system is unwieldy when calculating times before AD 1 because he did not account for a Year 0. More recently, some astronomers and scientists have opted to number years by a doubly infinite series of positive and negative numbers: -2, -1, 0, 1, 2. So according to this newer astronomical system, the first millennium began with the year 0 and the new millennium begins in two weeks. Maybe.