Idus Martii in Latin, refers to the 15th day of March in the Roman calendar. In ancient Rome, the Ides were considered an important marker for certain religious observances and political activities, including the settling of debts and the payment of taxes. They were also important dates for the performance of public ceremonies, such as the opening of the gladiatorial games.
Romans counted backwards from three specific points in the month: the Nones - fell on the 5th or 7th day, nine days before the Ides), the Ides - fell on the 13th day for most months, but on the 15th day for March, May, July, and October, and the Kalends - the 1st day of the following month.
The Romans generally specified due dates for financial obligations by the Ides and, since they allowed a quarter to get previous years’ corporate debts to the government, March 15 was the day such debts were due. It was, essentially, “tax day.” Ironically, this became true under Julius Caesar as he instituted the “Julian Calendar,” which moved the traditional New Year’s celebration from January 1 to March 15.
