About 13 kilometers north of the Azraq Junction, on the highway to Iraq, you will find the large black fortress of Qasr al-Azraq. The present form of the castle dates back to the beginning of the 13th century AD. Crafted from local black basalt rocks, the castle exploited Azraq’s important strategic position and water sources. The first fortress here is thought to have been built by the Romans around 300 AD, during the reign of Diocletian. The structure was also used by the Byzantines and Umayyads. Qasr al-Azraq underwent its final major stage of building in 1237 AD, when the Mamluks redesigned and fortified it. In the 16th century the Ottoman Turks stationed a garrison there, and Lawrence of Arabia made the fortress his desert headquarters during the winter of 1917, during the Great Arab Revolt against the Ottoman Empire. The castle is almost square, with 80-meter long walls encircling a central courtyard. In the middle of the courtyard is a small mosque that may be from Umayyad times, along with the main well. At each corner of the outer wall, there is an oblong tower. The primary entrance is a single massive hinged slab of granite, which leads to a vestibule where one can see carved into the pavement the remains of a Roman board game. Above the entrance area is the chamber that was used by Lawrence during his stay in Qasr al-Azraq. The caretaker of the castle has a collection of photographs of Lawrence; in fact, his father was one of the Arab officers who served with the legendary Brit.