Calends

Calends, from the Latin Kalendae, designated the first day of each month in the ancient Roman calendar. The term also referred to the dating system that organized days around three fixed points each month: the Kalends (the first day), the Nones (usually the fifth or seventh), and the Ides (usually the thirteenth or fifteenth). In practice, Romans dated events by counting forward from or backward toward these markers, using terms such as ante diem, bien diem, and pridie to indicate the number of days before a Kalends, Nones, or Ides.

Most months had Nones on the 5th and Ides on the 13th; in March, May, July, and October the Nones fell on the 7th and the Ides on the 15th. The days between these points were named with reference to the next upcoming marker, and days before aKalends, Nones, or Ides were described as being a certain number of days before that marker. The phrase pridie Kalendas Martias, for example, means the day before the Kalends of March.

Historically, the pre-Julian calendar began the year in March, with the Kalends of January appearing on the winter boundary; Julius Caesar’s calendar reform in 46 BCE established January 1 as the start of the year and created the solar-based Julian year, though the basic practice of using Kalends, Nones, and Ides for dating continued in literary and inscriptional Latin.

The term Kalendae is the etymological source of the English word calendar. In Roman literature, references to the Kalends, Nones, or Ides supplied precise anchors for dates and events.