Enna (Castruggiuvanni in Sicilian) is an Italian municipality that is the capital of the free municipal consortium of the same name in Sicily. It was called Castrogiovanni until 1927, when it resumed its ancient name of Enna. The city was called Urbs Inexpugnabilis by the Romans because of its impregnability . In the previous three millennia it has been an almost impregnable stronghold of Siculians, Greeks, Romans, Byzantines, Arabs, Normans, Swabians, and Aragonese. Its main historical monuments are the castle, the Fortress of Ceres and the cathedral.