Janus gave January its name in ancient Roman tradition and symbolized looking backward and forward.
Janus was the Roman god of beginnings, transitions, gates, passages, and time. Roman artists commonly showed him with two faces: one looking toward the past and the other toward the future. That image made him especially suitable for the opening month of the Roman calendar.
The Latin name for January was Ianuarius, derived from Ianus, the Latin form of Janus. The month became associated with new beginnings and the start of official business after the calendar reforms traditionally linked with King Numa Pompilius and later Julius Caesar.
Janus is often confused with a Greek god because many Roman deities have Greek counterparts, but he has no exact Greek equivalent. New Year's customs involving reflection and resolutions echo the same past-and-future symbolism, although modern celebrations are not direct Roman religious ceremonies.