The temple might have been begun by Tarquin the Proud and inaugurated in 497 BC. Rebuilt under Augustus, then again under Diocletian, it was built on a high buttress of 5 meters. It housed the public treasure (ærarium). One also used to deposit there the ensigns of the legions during the time between the campaigns, as well as an official exemplary of the laws. During the Empire, the old Treasure of Saturn became simply the municipal fund of Rome. Today still stand eight superb columns of the pronaos.