The ancient Roman God Janus, or more properly Ianus, is the God of beginnings, endings, transitions, times, doorways, gateways, passageways, movement and traveling. He is depicted as having two faces because he sees both the past and the future and is looking both and where you’ve been and where you’re going. He was ritually invoked by the priests at the beginning of each ceremony for all the other Gods as he reigns as guardian of the gates between worlds and thus intermediary between mortals and the divine.
The Roman month Ianuarius (January) was named for him. His name may have come from the Latin word ire “to go” and from it was derived the word ianua “door” and the ceremonial archways in ancient Rome were called jani (singular janus) the most famous being the Janus Geminus whose doors were closed during peacetime and open during wartime.