September (Roman month) was adjusted to September 1 in the 5th century to coincide with the tax year. September (Roman month) September (from Latin "septem", "seven") or mensis September was originally the seventh of ten months on the ancient Roman calendar that began with March ("mensis Martius", "Mars' month"). It had 29 days. After the reforms that resulted in a 12-month year, September became the ninth month, but retained its name. September followed what was originally Sextilis, the "sixth" month, renamed "Augustus" in honor of the first Roman emperor, and preceded October, the "eighth" month that like September retained its numerical name contrary
Month quarter of a day shorter than the solar year and stellar events "wandered" through the calendar, it is referred to as Annus Vagus or "Wandering Year". The Nisga'a calendar coincides with the Gregorian calendar with each month referring to the type of harvesting that is done during the month. This calendar was proposed during the French Revolution, and used by the French government for about twelve years from late 1793. There were twelve months of 30 days each, grouped into three ten-day weeks called "décades". The five or six extra days needed to approximate the tropical year were placed after