September (Roman month)
September was originally the seventh month in the year of office of the Roman calendar as well as precursors of September today. The month of September had original 29 days; His name derives from the Latin term for septem "seven" and corresponds to the Etruscan month Celius.
In the year 153 BC, the annual commencement of the year was moved to January 1, so the month of September moved to the ninth place in the year of office. After the calendar reform of Gaius Julius Caesar was in the Julian calendar from the year 45 BC by the insertion of an additional day for an extension to 30 days.