Roman Festival Calendar

Romans counted towards three fixed days in each month: the Kalends (the 1st), the Nones (the 5th, or the 7th in March, May, July and October) and the Ides (the 13th, or the 15th in those same months). Any other day was "so many days before" the next one, counting inclusively — so 2 October is ante diem VI Nonas Octobres, six days before the Nones. In a leap year the extra day was not added at the end of February but by doubling the sixth day before the Kalends of March, the bissextum.

The hours shown are Roman seasonal hours for the city of Rome: daylight from sunrise to sunset is split into twelve horae, so an hour is longer in summer than in winter, and the night into four watches, vigiliae. Years are counted ab urbe condita, from the traditional founding of Rome in 753 BC.

The month pictures come from the Mosaic of the Months from Thysdrus (El Djem, Tunisia), early 3rd century AD.