January will shortly be here and the month is named after the Roman God Janus. Janus is an ancient Roman, composite, obscure god who is associated with doorways, beginnings, and transitions. He is usually a two-faced god that looks to the future and the past. The explanation for this belief being that one must emerge through a door or gate in order to enter into a new place. Therefore, the Romans considered Janus as the obvious choice for the first month of their year.
The ancient Romans called this month Ianuarius, which is not so far removed from the modern-day "January," taken from the Etruscan word jauna which means "door". Originally, however, Janus was honored on the first day of every month, in addition to being worshipped at the beginning of planting season and again at the harvest.