Janus, the two-faced Roman god, gave January its name and symbolically links the past with the future.
Roman tradition represented Janus with two faces looking in opposite directions. This imagery suited thresholds, doorways, beginnings, transitions, and changes of state. A new year similarly looks backward at the year that ended and forward toward the year ahead.
The Latin month name Ianuarius was derived from Janus. January eventually became the first month of the Roman calendar, although Roman calendars and practices changed over time. The month’s association with beginnings helped preserve Janus’s connection with New Year observances.
Janus was not simply a god of time. He was also associated with entrances and exits, and Roman religious rites commonly invoked him first. The month name survives in many modern languages, including English January, even though the deity’s name is less familiar outside classical history.