One of the historical castles in Jordan. The Azraq Castle was built of black basalt. Azraq Castle is located in the middle of the Azraq Oasis, one hundred kilometers east of Amman. The castle was built mainly to be a fortress for the Nabataeans or the Romans, then the Mamluks rebuilt it again in the thirteenth century AD. Azraq Oasis contains the only permanent source of pure water in the surrounding desert, which is about twelve thousand square miles. A number of sources indicate that the Greeks and Romans were the first to establish this castle, which was used, rebuilt, or repaired and restored by the Byzantines, the Umayyads, the Turks, the Ayyubids, the Mamluks and the Arabs. The inscriptions inscribed on the stones inside the castle indicate that the castle was established for the benefit of the Emperor “Diocletian” and the Emperor “Maximian” between the years 285 AD and 305 AD. In its construction, the Umayyads rebuilt the castle and established a set of walls and dams. In the days of the Great Arab Revolt, “Lawrence of Arabia” took the castle as a base.