Once misidentified as the Temple of Vesta, it was correctly attributed to Hercules Victor by Camille de Tournon, Napoleon’s Prefect of Rome. The temple is notable for its status as the earliest surviving marble structure in Rome, built using Greek marble, and has inspired numerous architectural designs through the centuries.

Despite (or perhaps due to) the Forum Boarium's role as the cattle market for ancient Rome, the Temple of Hercules is the subject of a folk belief claiming that neither flies nor dogs will enter the holy place. The temple is the earliest surviving mostly intact marble building in Rome and the only surviving one made of Greek marble.

circa 150 BCE

Dating from the later 2nd century BCE and erected by L. Mummius Achaicus, conqueror of the Achaeans and destroyer of Corinth, or by Marcus Octavius Herrenus, the temple is 14.8 m in diameter and consists of a circular cella within a concentric ring of twenty Corinthian columns 10.66 m tall, resting on a tuff foundation. These elements supported an architrave and roof, which have disappeared.

Its major literary sources are two almost identical passages, one in Servius' commentary on the Aeneid (viii.363) and the other in Macrobius' Saturnalia. Though Servius mentions that aedes duae sunt, "there are two sacred temples", the earliest Roman calendars mention but one festival, on 13 August, to Hercules Victor and Hercules Invictus interchangeably.

In the 1st century CE, the temple was hit with some sort of disaster as 10 columns were replaced with Luna marble, which is similar to the original but not an exact replica. By 1132, the temple had been converted to a church, known as Santo Stefano alle Carozze (St. Stephen 'of the carriages'). In 1140, Innocent II converted the temple into a Christian church dedicating it to Santo Stefano.

Additional restorations (and a fresco over the altar) were made in 1475. A plaque in the floor was dedicated by Sixtus IV. In the 12th century, the cella wall was replaced with brick-faced concrete and windows were added as well.

In the 17th century, the church was rededicated to Santa Maria del Sole ("St. Mary of the Sun"). The temple and the Temple of Vesta in Tivoli were an inspiration for Bramante's Tempietto and other High Renaissance churches of centralized plan. Between 1809 and 1810, the surrounding ground level was lowered and the temple was restored once again. The temple was recognized officially as an ancient monument in 1935 and restored in 1996.

circa 150 BCE

The temple is 14.8 meters in diameter and consists of a circular cella within a concentric ring of twenty Corinthian columns 10.66 m tall, resting on a tuff foundation. The original wall of the cella, built of travertine and marble blocks, and nineteen of the originally twenty columns remain but the current tile roof was added later. Palladio's published reconstruction suggested a dome, though this was apparently erroneous. The temple is the earliest surviving marble building in Rome.

The temple's original dedication is dated back to circa 143–132 BCE, a time when intense construction was taking place in Portus Tiberinus. In the 12th century CE, the cella wall was replaced with brick-faced concrete, and windows were added. Additional changes, including restorations and frescoes, reflect the temple's transition through various periods of Roman and post-Roman architectural developments.