The Temple of Jupiter dominates the north side of the Forum, with Mount Vesuvius scenically rising behind. When the colony was founded (80 BC), the temple underwent a radical renovation and became a real Capitolium with the three cult statues of Jupiter, Juno and Minerva, which looked like those of the Capitolium in Rome, placed on a high base so as to make them visible to whoever passed in the Forum square.

The new works extended the cell of the temple, in which a rich mosaic floor with marble elements was laid. The favissae open within the basis, and are underground areas originally used for the offerings to the gods. According to some studies, in time they probably protected the public treasury of the city. There were two equestrian statues on the sides of the basis of the Capitolium, as evidenced by the relief found in the lararium of the house of Lucio Cecilio Giocondo.

Date of excavation: 1810; 1816; 1820.