In Roman Mythology, Janus was the god of gates, doors, beginnings, endings and doorways. The month of January was named for him. He was usually depicted as Janus Geminus (twin Janus) or Bifrons, with two faces looking in opposite directions. In some places he was Janus Quadrifrons (the four-faced). He was associated with Etruscan Ani.
Symbolism: the god of change and transitions such as the progression of past to future, of one condition to another, of one vision to another, and of one universe to another.
Janus was worshipped at the beginnings of the harvest and planting times, as well as marriages, births and other beginning. He was representative of the middle ground between barbarity and civilization, rural country and urban cities and youth and adulthood.
He supposedly came from Thessaly in Greece and shared a kingdom with Camese in Latium. They had many children, including Tiberinus. Janus and his later wife, Juturna, were the parents of Fontus. He had another wife name Jana.
As the sole ruler of Latium, Janus heralded the Golden Age, introducing money, laws and agriculture (making him a culture hero).
When Romulus and his men stole the women of the Sabines, Janus caused a hot spring to erupt, causing the would-be attackers to flee. In honor of this, the doors to his temples were kept open during war so that he could easily intervene. The doors and gates were closed during peace.
His two faces (originally, one was always bearded, one clean-shaven; later both bearded) originally represented the sun and the moon. He was usually depicted with a key. Janus head is a popular phrase for deception, that is, when action does not match speech.
See also: Bifrons (demon)