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 The emperor Commodus renamed the month after either himself or Hercules—an innovation that was repealed after his murder in 192.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.
In the agricultural year
For the month of September, ancient farmers' almanacs (menologia rustica) take note of the autumnal equinox on September 24, and the equal number of daylight and nocturnal hours. They note that the month began with the sun in the astrological sign of Virgo, and was under the guardianship (tutela) of Volcanus (the god Vulcan). On an unspecified date an Epulum Minervae (Banquet of Minerva) is to be held, probably as part of the general epulum on the Ides.
The farmer is instructed to coat wine vessels with pitch, pick apples, and loosen the compacted soil around trees. In his agricultural treatise, Varro assigns farmers additional tasks in the period from the rising of Sirius to the equinox. Straw must be cut, haystacks pitched, arable land ploughed, fodder gathered, and well-watered meadows mown a second time. Columella specifies that sloping ground should be ploughed between the Kalends (1st)and the Ides (13th).
Equinox and medical theory
The Aëtius parapegma is an almanac that appears as a chapter in the 6th-century Tetrabiblos of Aëtius of Amida. It treats the rising and setting of constellations, weather forecasting, and medical advice as closely intertwined, and notes of the equinox (placed on September 25) thatThere is the greatest disturbance in the air for three days previous. Thus it is necessary to be careful neither to phlebotomize, nor purge, nor otherwise to change the body violently from the 15th of September through the 24th. The passage is presented as advice for physicians, based on the principle that "the bodies of healthy people, and especially those of sick people, change with the condition of the air".
Iconography of the month
The vintage, with bunches or baskets of grapes, predominates in both verbal and visual allegories of September, particularly in mosaics depicting the months. In the manuscripts that preserve the Calendar of Filocalus (354 AD), September is represented by a nude male wearing only a long light scarf over one shoulder. The conventional bunch of grapes appears under his left hand, outstretched to hold a basket, on the top of which are arrayed five puzzling picks or skewers. Over his right shoulder is placed a basket holding two pyramids of six figs or small flasks. A vessel, presumably to receive the new wine, is sunk into the ground on either side of him. Over the one to his right, he dangles a lizard on a string, a motif that recurs in imagery associated with Dionysus, the god of wine. The exact significance of the lizard is uncertain. It may represent a magico-medical charm to ensure healthy wine, with the lizard either a potent lustration or the potential damage to be warded off. The lizard is also an attribute of Apollo Sauroctonos.