The Romans did not number days of a month sequentially from the 1st through the last day. Instead, they counted back from the three fixed points of the month: the Nones (5th or 7th, depending on the length of the month), the Ides (13th or 15th), and the Kalends (1st) of the following month. The Nones of January fell on the 5th, and the Ides on the 13th. The last day of January was the "pridie Kalendas Februarias," "day before the Kalends of February". Roman counting was inclusive; January 9 was "ante diem V Idūs Ianuarias", "the 5th day before the Ides (13th) of January," usually abbreviated "a.d. V Id. Ian." (or with the "a.d." omitted altogether); January 23 was "X Kal. Feb.", "the 10th day before the Kalends of February."