In ancient Roman religion and myth, Janus (/ˈdʒeɪnəs/; Latin: Ianus, pronounced [ˈjaː.nus]) is the god of beginnings, gates, transitions, time, duality, doorways, passages, and endings. He is usually depicted as having two faces, since he looks to the future and to the past. It is conventionally thought that the month of January is named for Janus (Ianuarius), but according to ancient Roman farmers’ almanacs Juno was the tutelary deity of the month.
1- Varro apud Augustine De Civitate Dei VII 9 and 3; Servius Aen. I 449; Paulus ex Festus s. v. Chaos p. 45 L