Janus.

    One of the earliest of native Italian gods, Janus has no equivalent in Greek mythology. To the Romans, he was the god of gates and doorways and of the New Year and beginnings in general. He was the first to be named in any list of gods invoked in prayer, superseding even Jupiter, and the first to receive a portion of the sacrifice. His name was given to the first of the Roman months. His symbol, common in sculpture and coinage, was a double-faced head, looking both ahead and behind. His temple on the Janiculum in Rome was famous for its two sets of doors—situated at the western and eastern ends of an arched passageway—that were kept closed in times of peace and opened in times of war.
     Janus did not figure strongly in myth. One story describes him as an early king of Latium and the father of Tiberinus, who drowned in a river that from then on bore his name, the Tiber. Janus was believed to have received Saturn (Cronus) when he was driven from Greece by Zeus.
    
     Classical Sources. Virgil, Aeneid 7.180, 7.610, 8.357,12.198. Livy, Ab urbe condita 1.19.2. Ovid, Metamorphoses 14.785!?.; Fasti 1.63—299.