The Roman god Janus gives his name to January, the month that begins the Gregorian year.
Janus was associated with beginnings, transitions, doorways, passages, and endings. He was often depicted with two faces, one looking forward and the other looking backward, making him a fitting symbolic figure for the transition from one year to the next.
The Latin name for January was Ianuarius, derived from Janus. January became the first month in the Roman calendar during calendar reforms traditionally associated with the second century BCE. The Gregorian calendar, introduced in 1582 and now used as the international civil calendar, retained January as the first month.
The month’s connection with New Year’s celebrations is therefore both calendrical and symbolic. Janus is not the god who gives December its name, and January’s placement at the start of the modern year reflects later calendar development rather than a universal ancient arrangement.