Note: Do not rely on this information. It is very old.
JanusJanus, an Italian divinity, the god of opening and beginning (Lat. Januazzz.gs.te). He took precedence even of Jupiter, and is supposed by some authorities to have been of Etruscan origin. The hill called Janiculum, on the N. of the Tiber, was probably the original seat of his worship. He is represented on coins with two faces looking in opposite directions. He carries keys and is crowned with laurel. The gates of his temple at Rome were open in time of war, and shut in time of peace. There was originally an archway on the site, from which the troops marched out to war.
January, or the first month of the agricultural yeai took its name from the God Janus.