In Roman mythology, Janus gave January its name and looked both backward and forward.
Janus was the Roman god of beginnings, transitions, doorways, gates, and passages. Artists commonly showed him with two faces: one facing the past and the other facing the future. That symbolism made him especially associated with turning points such as the change from one year to the next.
The Roman month Ianuarius, later called January in English, was named for Janus. January became the first month of the Roman calendar after calendar reforms, although older Roman traditions had treated March as the year's beginning.
Janus is often confused with a Greek equivalent, but he has no exact Greek counterpart. New Year's celebrations do not worship Janus today; the connection survives mainly through the month's name and the familiar imagery of looking back and ahead.