In Roman mythology, Jupiter was the king of the gods, and the god of sky and thunder. He is the equivalent of Zeus in the Greek pantheon. He was called Iuppiter Optimus Maximus (Jupiter Best, Greatest); as the patron deity of the Roman state, he ruled over laws and social order. He was the chief god of the Capitoline Triad, with Juno and Minerva. In Latin mythology Jupiter is the father of the god Mars. Therefore, Jupiter is the grandfather of Romulus and Remus, the legendary founders of Rome. Jupiter was venerated in ancient Roman religion, and is still venerated in Religio Romana Neopaganism.
The name of the god was also adopted as the name of the planet Jupiter, and was the original namesake of Latin forms of the weekday known in English as Thursday but originally called Iovis Dies in Latin, giving rise to jeudi in French, jueves in Spanish, joi in Romanian, giovedì in Italian and dijous in Catalan.
The building was begun by Tarquinius Priscus and completed by the last king of Rome, Tarquinius Superbus, although it was inaugurated, by a tradition recorded by the historians, on September 13, at the beginning of the Republican era, 509BCE.
The temple building stood on a high podium with an entrance staircase to the front. On three of its sides it was probably surrounded by a colonnade, with another two rows of pillars drawn up in line with those on the façade of the deep pronaos which precedes the three cellae, ranged side by side in the Etruscan manner, the central one being wider than the other two.
The surviving remains of the foundations and of the podium, most of which lie underneath Palazzo Caffarelli, are made up of enormous parallel sections of walling made in blocks of grey tufa-quadriga stone (cappellaccio) and bear witness to the sheer size of the surface area of the temple's base (about 55 x 60 m).
On the roof a terracotta auriga, made by the Etruscan artist Vulca of Veii in the 6th Century BCE, commissioned by Tarquinius Superbus; it was replaced in 296BCE, by a bronze one. The cult image, by Vulca, was of terracotta; its face was painted red on festival days (Ovid, Fasti, 1.201f). Beneath the cella were the favissae, or underground passages, in which were stored the old statues that had fallen from the roof, and various dedicatory gifts.
The temple was rebuilt in marble after fires had worked total destruction in 83BCE, when the cult image was lost, and the Sibylline Books kept in a stone chest. Fires followed in 69CE, when the Capitol was stormed by the supporters of Vitellius and in 80CE.
In front of the steps was the altar of Jupiter (ara Iovis). The large square in front of the temple (the Area Capitolina) featured a number of temples dedicated to minor divinities, in addition to other religious buildings, statues and trophies.
Its dilapidation began in the fifth century, when Stilicho carried off the gold-plated doors and Narses removed many of the statues, in 571CE.
When Hadrian build Aelia Capitolina on the site of Jerusalem, a temple to Jupiter Capitolinus was built in the place of the destroyed Temple in Jerusalem.
Juppiter Tonans ("Thundering Jove") was the aspect (numen) of Jupiter venerated in the Temple of Juppiter Tonans, which was vowed in 26BCE by Augustus and dedicated in 22 on the Capitoline Hill; the Emperor had narrowly escaped being struck by lightning during the campaign in Cantabria. An old temple in the Campus Martius had long been dedicated to Juppiter Fulgens. The original cult image installed in the sanctuary by its founder was by Leochares, a Greek sculptor of the 4th Century BCE. The sculpture at the Prado (illustration) is considered to be a late first century replacement commissioed by Domitian. The Baroque-era restoration of the arms gives Jupiter a baton-like scepter in his raised hand.