Used to be the seventh month of the year and in Latin, septem means 'seven'.
Until Julius Caesar's calendar reform of 45BC, September had only 29 days.
The Anglo-Saxons called September Gerst Monath (Barley Month) or Haefest Monath (Harvest Month) celebrating the barley harvest.
Key holidays in September are Labor Day, Mid Autumn Festival and Autumnal Equinox Day.