The Arch of Augustus was the triumphal arch of Augustus, located in the Roman Forum. It spanned the road between the Temple of Castor and Pollux and the Temple of Caesar, near the Temple of Vesta. Built in 20 BC, it commemorated the return of the Parthian standards and replaced the earlier Arch of Octavian built on the same spot in 29 BC, to commemorate the Battle of Actium (31 BC) against Mark Antony and Cleopatra.