Jupiter, in Roman mythology, the supreme god. Though principally a sky god in charge of all atmospheric conditions, he had many special functions. In his most important temple, on the Capitoline Hill, he was worshiped as god of the state and was called Optimus Maximus (The Best and Greatest). He directed the course of human affairs, and revealed future events by producing omens in the heavens. White, the color of the light of day, was sacred to Jupiter. His priests wore white robes, white animals were sacrificed to him, and white horses drew his chariot.
Jupiter was identified with the Greek god Zeus, and many of the early stories about him correspond to those told of Zeus.Jupiter was the supreme Roman god.