The most important and impressive temple in ancient Rome was dedicated to the Capitoline Triad: Jupiter, Juno and Minerva. It was started by the first Etruscan king Tarquinio Prisco and continued by Tarquinio il Superbo. Its unveiling only occurred during the first years of the Republic in 509 BC under Orazio Pulvillo. 

The size of the building (circa m 53 x m 63) makes it the biggest tuscanic temple ever build. The facade and the two sides had six columns arranged on three lines, the end side was blind. On top of the pediment there was the quadriga, also made of terracotta, work of the Etruscan sculptor Vulca who, probably is the author of the famous Apollo di Veio kept at the Museum of Villa Giulia. 

In 296 BC, the terracotta quadrigia was substituted with a bronze one, maybe a work of the Ogulnii brothers, the same that maybe did the Lupa capitolina (Capitoline she-wolf). The cult statue, probably inspired by the one of Zeus in Olimpia, a work of Fidia, was done by the Greek sculptor Apollonios. A copy of the Capitoline Triad can be seen in the Museum of Palestrina.The building was restored many times, one of which under Silla. 

The archaic temple was destroyed by many fires, then rebuilt in marble. Some coins and a relief of Marco Aurelio, at present in the Capitoline Museum, which represents four columns on the front, give the picture of the last phase of the temple. It is known, furthermore, that the roof was covered by gold leafs, removed by the barbaric invasions. 

Recent excavations made in the Giardino Romano inside Palazzo Nuovo have brought to light a great part of the basement of the temple which is formed by squared blocks of gossan.