He also built the Temple of Caesar, the Baths of Agrippa, and the Forum of Augustus with its Temple of Mars Ultor. Other projects were either encouraged by him, such as the Theatre of Balbus, and Agrippa's construction of the Pantheon, or funded by him in the name of others, often relations (e.g. Portico of Octavia, Theatre of Marcellus). Even his Mausoleum of Augustus was built before his death to house members of his family. To celebrate his victory at the Battle of Actium, the Arch of Augustus was built in 29 BC near the entrance of the Temple of Castor and Pollux, and widened in 19 BC to include a triple-arch design.