The quadrangular area in the north-eastern sector of the Castro Pretorio district in Roman times was the seat of the Castra Paetoria where the main body of the imperial guard resided: the Praetorian Guard. Even today the area is largely used for military purposes and is home to the Macao Barracks and the Pio IX Barracks.

Cover: Author's elaboration on orthophotos from the National Geoportal of the Ministry of the Environment and Energy Security https://www.mase.gov.it