Janus  (´nus ).—An old Latin deity, the sun-god. He presided over the beginning of everything; he opened the year, and hence the first month of the year was called after him. He was the porter of heaven. His temple in the Forum had two doors opposite each other, which in time of war were open and in time of peace were shut. The latter happened only thrice in Roman history. He is represented with a face at the back, as well as one at the front, of his head.