Jupiter/Zeus. Jupiter, also known as Jove, is the god of the sky and thunder and king of the gods in Ancient Roman religion and mythology. Jupiter was the chief deity of Roman state religion throughout the Republican and Imperial eras, until Christianity became the dominant religion of the Empire. In Roman mythology, he negotiates with Numa Pompilius, the second king of Rome, to establish principles of Roman religion such as offering, or sacrifice. Jupiter is usually thought to have originated as an aerial god. His identifying implement is the thunderbolt and his primary sacred animal is the eagle, which held precedence over other birds in the taking of auspices and became one of the most common symbols of the Roman army. The two emblems were often combined to represent the god in the form of an eagle holding in its claws a thunderbolt, frequently seen on Greek and Roman coins. As the sky-god, he was a divine witness to oaths, the sacred trust on which justice and good government depend. Many of his functions were focused on the Capitoline Hill, where the citadel was located. In the Capitoline Triad, he was the central guardian of the state with Juno and Minerva. His sacred tree was the oak. The Romans regarded Jupiter as the equivalent of the Greek Zeus, and in Latin literature and Roman art, the myths and iconography of Zeus are adapted under the name Iuppiter. In the Greek-influenced tradition, Jupiter was the brother of Neptune and Pluto, the Roman equivalents of Poseidon and Hades respectively. Each presided over one of the three realms of the universe: sky, the waters, and the underworld. The Italic Diespiter was also a sky god who manifested himself in the daylight, usually identified with Jupiter. Tinia is usually regarded as his Etruscan counterpart. The Romans believed that Jupiter granted them supremacy because they had honoured him more than any other people had. Jupiter was the fount of the auspices upon which the relationship of the city with the gods rested. He personified the divine authority of Rome's highest offices, internal organization, and external relations. His image in the Republican and Imperial Capitol bore regalia associated with Rome's ancient kings and the highest consular and Imperial honours. Bas-relief of Roman driver in four-horse chariot, facing left. The consuls swore their oath of office in Jupiter's name, and honoured him on the annual feriae of the Capitol in September. To thank him for his help, they offered him a white ox with gilded horns. A similar offering was made by triumphal generals, who surrendered the tokens of their victory at the feet of Jupiter's statue in the Capitol. Some scholars have viewed the triumphator as embodying Jupiter in the triumphal procession. Jupiter's association with kingship and sovereignty was reinterpreted as Rome's form of government changed. Originally, Rome was ruled by kings; after the monarchy was abolished and the Republic established, religious prerogatives were transferred to the patres, the patrician ruling class. Nostalgia for the kingship was considered treasonous. Those suspected of harbouring monarchical ambitions were punished, regardless of their service to the state. In the 5th century BC, the triumphator Camillus was sent into exile after he drove a chariot with a team of four white horses, an honour reserved for Jupiter himself. When Marcus Manlius, whose defense of the Capitol against the invading Gauls had earned him the name Capitolinus, was accused of regal pretensions, he was executed as a traitor by being cast from the Tarpeian Rock. His house on the Capitoline Hill was razed, and it was decreed that no patrician should ever be allowed to live there. Capitoline Jupiter found himself in a delicate position: he represented a continuity of royal power from the Regal period, and conferred power on the magistrates who paid their respects to him; at the same time he embodied that which was now forbidden, abhorred, and scorned. During the Conflict of the Orders, Rome's plebeians demanded the right to hold political and religious office. During their first secessio, they withdrew from the city and threatened to found their own. When they agreed to come back to Rome they vowed the hill where they had retreated to Jupiter as symbol and guarantor of the unity of the Roman res publica. Plebeians eventually became eligible for all the magistracies and most priesthoods, but the high priest of Jupiter remained the preserve of patricians.