Roman Mythology : Janus god of gates, doors , beginnings and endings

Janus, the mythological “god of doors, gates, beginnings and endings”. This is the definition most commonly found.
Firstly, name is from Latin, Ianus.
Janus is from Roman mythology, and unlike the majority of Roman mythological deities there is no Greek origin or equivalent.
A number of dictionaries refer to “gates and doors” and do not give much attention to the “Beginnings an Endings” part. The beginnings and endings appear to refer to a transition process, both tangible and abstract.
Examples: The progress or transition from the past to the future
Births and marriages.
Janus is usually depicted with two faces, one facing forwards, the other backwards, depicting his gift of looking into the past and the future. Some references say the one face was bearded and the other clean-shaven. But, a number of images depict both faces fully bearded. Maybe this morphed with the passing of time. Some references refer to four faces.
Anyhow, The month of January is named after Janus, being the beginning or entrance to the New Year.
The word Janitor also originates from Janus, as the keeper or custodian of halls.
He was often depicted holding a key, as he was the protector of the King’s treasure.
When Rome was at war, which was probably very often during these times, the doors to the temple of Janus ( Ianus Geminus, or Portae Belli, the Gates of War? ) were kept open, and closed in the time of peace. Why? Could not really determine why…..
For detailed information, Wikipedia is a good place to start.
Image from Wikipedia