Janus, the ancient Roman god of beginnings, gave January its name and was honored at the start of the year.
Janus was associated with doors, gates, transitions, and new beginnings. Roman artists often represented him with two faces, one looking forward and one backward, a fitting image for leaving one year behind while entering another. The Latin month name Ianuarius was derived from his name.
Roman New Year observances did not always begin on January 1. The Roman calendar changed over time, and January 1 became especially important after calendar reforms and political practice established it as the start of the consular year. The month retained its connection with Janus because its position made it a natural symbol of transition.
Janus is often mistakenly treated as a god of time in exactly the same sense as later figures such as Father Time. His central Roman associations were thresholds and beginnings. The modern month name preserves that older religious and linguistic connection.