October (Roman month) October (Roman month) October (from Latin "octo", "eight") or mensis October was the eighth of ten months on the oldest Roman calendar. It had 31 days. October followed September (from "septem", "seven") and preceded November ("novem", "nine"). After the calendar reform that resulted in a 12-month year, October became the tenth month, but retained its numerical name, as did the other months from September through December. Some of the observances in October marked the close of the season for military campaigning and farming, which commenced in March ("Martius", "Mars' month"). October was under the guardianship "(tutela)" of Mars. The Romans
September (Roman month) to the period August 19 to September 17. The Romans did not number days of a month sequentially from the first day through the last. Instead, they counted back from the three fixed points of the month: the Nones (5th or 7th, depending on the month), the Ides (13th or 15th), and the Kalends (1st) of the following month. The Nones of September was the 5th, and the Ides the 13th. The last day of September was the "pridie Kalendas Octobrīs," "day before the Kalends of October". Roman counting was inclusive; September 9 was "ante diem V Idūs Septembrīs", "the