One of the most enduring institutions of Augustus was the establishment of the Praetorian Guard in 27 BC, originally a personal bodyguard unit on the battlefield that evolved into an imperial guard as well as an important political force in Rome. They had the power to intimidate the Senate, install new emperors, and depose ones they disliked; the last emperor they served was Maxentius, as it was Constantine I who disbanded them in the early 4th century and destroyed their barracks, the Castra Praetoria.