Overview
Qsar Bashir is a Roman fort (castellum) located 80 km south of Amman. This isolated military outpost is a link in the Limes Arabica, the 2,400 km-long line of defense running from the Gulf of Aqaba all the way to northern Syria, defending the Empire’s southeastern frontier against Arab marauders. It also happens to be the best-preserved specimen of the classic Diocletianic quadriburgium common to the frontiers of the Empire. Its original name, Castra Praetorii Mobeni, is still visible on the cracked lintel above the main entrance. An inscription also bears witness to the reigns of emperors Diocletian and Maximianus—along with their respective caesars, Flavius Valerius Constantius and Galerius Valerius Maximianus—which narrows its date of construction to sometime between 293 and 306 CE.
These quadriburgium-style forts vary in size and plan. This one is irregularly square, with walls averaging roughly 56 m in length. Squared towers guard each of the four corners, with two additional towers flanking the main gate. The towers stood three stories high, with each stage divided into three rooms each. The upper floors were supported by stone slabs set into the walls and supported by arches. Watchmen and archers gained access to the upper stories of the towers, as well as the rampart platforms, by climbing narrow stone staircases some about a meter wide. From the platforms atop each tower, watchmen could monitor movement across the valley and over the hills to the east. Cavalry detachments, which regularly patrolled the region, could then be dispatched to investigate any suspicious activity.
The outer walls of the fort are about 1.5 m near the base and stand roughly seven meters high. Known as “curtain walls” because they appear to be draped between towers, they surround an open courtyard and comprise a series of rooms on two floors. A rampart lines the perimeter of the wall, accessed by a walkway passing through doors in each tower. As a citadel, Qsar Bshir would have housed a cavalry unit, so it is not surprising that up to 23 of the 26 ground floor rooms, each with mangers recessed into the rear walls, appear to have served as stables able to accommodate three horses each. The second-floor rooms above the stables almost certainly served as barracks for calvary and foot soldiers.