Chronos is a god from Greek Mythology who is depicted as the personification of time. He is said to be incorporeal, and has a serpentine body with three heads - that of a human, a bull, and a lion. He and his consort Ananke circled the world-egg in the beginning and split it up to create the ordered universe of earth, sea, and sky.
He may - or may not - be the same entity as the Titan Cronus, son of Uranus and Gaia and father of Zeus. If not, he is usually part of a radically divergent mythology that may have originated outside Greece and been integrated at a later point.