For the Greeks and Romans, Jupiter was first and foremost the king of Olympus. He represented supreme authority over all the Olympian gods, becoming king when he overthrew his father Saturn (Chronos in Greek mythology).
Saturn ate his children at birth, afraid that they would usurp him. Jupiter and his brothers and sisters rebelled, and overthrew Chronos and the Giants to form the first generation of Olympian gods. Jupiter features in a good number of mythological episodes, and had many love affairs with mortal women, arousing the jealosuy of his wife Juno.
Jupiter was a heavenly power, the lord of thunder, wind and rain. He brought order and justice to Olympus and to earth. He was considered the king of all the gods.