Janus is the Roman god who gives January its name and is associated with looking backward and forward.
Roman tradition connected Janus with beginnings, transitions, doorways, gates, and endings. He is often depicted with two faces, one looking toward the past and one toward the future. That imagery makes him especially relevant to the passage from one calendar year to the next.
The month of January is named after Janus. In the Roman calendar reforms associated with the second century BCE, January became the first month of the consular year, although the history of the Roman calendar is complex and the beginning of the year changed at different times and places.
New Year’s customs today are not direct Roman ceremonies to Janus. However, the familiar idea that January represents reflection on the old year and hopes for the new one echoes the god’s traditional role. Janus should not be confused with Saturn, whose festival Saturnalia was held in December.