The Roman god honored by the month of January, whose two faces symbolize looking backward and forward, is Janus.
Janus was associated with beginnings, transitions, doorways, gates, and passages. Roman artistic representations commonly show him with two faces, allowing him to look in opposite directions. This image later became a powerful metaphor for New Year's Eve: people reflect on the year ending while anticipating the year ahead.
The month name January derives from Janus. In the Roman calendar, January 1 became an important civic date, especially after calendar reforms and the expansion of the consular year. Roman officials traditionally entered office on January 1 from 153 BCE, helping establish the date's administrative importance.
Janus is not the same figure as Saturn, the Roman god associated with the festival of Saturnalia. Nor is the two-faced image meant to suggest dishonesty in its original religious context. It represents thresholds and the ability to see both what has passed and what is beginning.