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 to its position on the calendar. A day was added to September in the mid-40s BC as part of the Julian calendar reform.

September has none of the archaic festivals that are marked in large letters for other months on extant Roman fasti. Instead, about half the month is devoted to the Ludi Romani, "Roman Games", which developed as votive games for Jupiter Optimus Maximus ("Jupiter Best and Greatest"). The Ludi Romani are the oldest games instituted by the Romans, dating from 509 BC. On the Ides of September (the 13th), Jupiter was honored with a public banquet, the Epulum Jovis. A nail-driving ritual in the temple marked the passing of the political year during the Republican era, and in the earliest period, the consuls took office on the Ides of September. The month was often represented in art by the grape harvest.

September was the birth month of no fewer than four major Roman emperors, including Augustus. The emperor Commodus renamed the month after either himself or Hercules—an innovation that was repealed after his murder in 192. In the Eastern provinces of the Roman Empire, the year began with September on some calendars, and was the beginning of the imperial tax year.

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