Janus, the two-faced Roman god, gave the month of January its name.
Janus was associated with beginnings, transitions, doorways, gates, and passages. Roman artists commonly represented him with two faces, one looking forward and the other backward. That image made him an especially fitting symbol for the turning from one year to the next.
The English word January comes through Latin Ianuarius, meaning the month of Janus. In the Roman calendar, January’s position and importance changed over time, but it became the first month of the Julian calendar introduced under Julius Caesar in 46 BCE and implemented in 45 BCE.
Janus was not simply a god of New Year’s celebrations in the modern sense. His broader role concerned thresholds and transitions of many kinds. The connection between his name and January is why the month is often linked symbolically with reflection on the past and anticipation of the future.