The second temple of the Forum Boarium, commonly known as the Temple of Vesta, was probably dedicated to Hercules Victor at the end of the 2nd century BC. It is the oldest marble building that has remained virtually intact in Rome. Circular in shape, it is surrounded by 20 columns of Corinthian order, although the original entablature and roof have been lost, presumably due to a dome.
Like the Temple of Fortuna Virilis, this temple was also converted into a church dedicated to St. Stephen in the 12th century, and later renamed St. Maria del Sole in the 16th century, due to an image found in the Tiber that was said to emit a ray of sunshine.
The temple of Hercules Victor, probably built at the end of the 2nd century BC and subject to interventions during the Tiberian period. An inscription found on its base revealed its true dedication to Hercules Olivarius and that the statue inside was the work of the Greek sculptor Skopas Minor. It is hypothesized that the architect responsible for its design may have been Ermodorus of Salamis, who also worked on the Temple of Jupiter Stator.
The architecture of the temple shows clear inspiration from Greek models of the 4th century BC, with particular reference to the Temple of Hercules Invictus, erected in 142 BC and lost in the 15th century. This structure, with steps instead of the traditional podium and marble decorations, reflects influences of late Hellenistic art.