As we flip the calendar from summer to fall, big changes start happening. One month you’re dressing up in a spooky costume, the next you’re carving up a turkey, and the next you’re singing carols in the snow. (And if you pay attention to retail stores’ decorations, you might never know what month you’re in.) But while September, October, November, and December are celebrated quite differently, they were all named in a similar manner by the ancient Romans.
The original Roman calendar had 10 months, beginning with March. The first four months of the year — March, April, May, and June — were named after gods and Latin verbs. The remaining months were named based on their order in the year. Quintilis and Sextilis — the original names of July and August — translate to “fifth month” and “sixth month.” Similarly, the names for September, October, November, and December corresponded to the (now-inaccurate) numbers of the months: septem (seven), octo (eight), novem (nine), and decem (10).
When January and February were officially added to create the Julian calendar around 150 BCE, every month on the Roman calendar shifted back two spots. Even though September is now the ninth month of the year, it remains the “seventh month” in a lexicographical sense. This quirk also applies to October, November, and December.
