Hadrian's Mausoleum - Roma - The building was originally built as a mausoleum for the emperor Hadrian, and was completed after his death by his successor, Antoninus Pius. The name, Castel Sant Angelo dates back to when Pope Gregory the Great, during a procession to plead for the end of a plague, saw an angel standing on the top of the castle sheathing its sword. This was interpreted as being a heavenly sign that the plague was about to end.
Base of the column of Antoninus Pius. AD 161. This side shows the apotheosis of AP and Faustina. The Campus Martius and Roma are personified in the bottom corners. The other sides of the column base show military reviews. New use of perspective and space to show depth in reliefs.