document porta praetoria

Under the Roman emperor Marcus Aurelius, the Castra Regina legionary camp was built on the southern bank of the Danube in the 2nd century AD. Like most Roman legionary camps of this size, Castra Regina also had four gates. 

The main gate, the Porta Praetoria, faced north toward the Danube as the exit gate of the legionary camp toward their enemies. It was built in response to the Marcomannic Wars, which necessitated the stationing of the Third Italian Legion at this location. Despite its severe destruction, the gate with its mighty ashlar blocks still conveys an impression of how strongly fortified this camp once was.