The Temple of Hercules Victor ('Hercules the Winner') (Italian: Tempio di Ercole Vincitore) or Hercules Olivarius is an ancient edifice located in Piazza Bocca della Verità, in the area of the Forum Boarium close to the Tiber in Rome (Italy). It is a monopteros, a round temple of Greek 'peripteral' design completely encircled by a colonnade. This layout caused it to be mistaken for a temple of Vesta until it was correctly identified by Napoleon's Prefect of Rome, Camille de Tournon. Wikipedia