Mobene (Qasr Bshir)

Qasr Bshir belongs to the chain of forts and watchtowers that is known as the Limes Arabicus and was meant to protect the province of Arabia against roaming desert nomads. They were not extremely dangerous or exceptionally violent, but their dromedaries made them swift, and if trouble arose, they could pillage large parts of the Roman countryside. The Limes Arabicus had to counter this threat, and Mobene was one of the fortifications.

The fort dominates a wide, stony plain, cut by several wadis that empty themselves in the Wadi Mujib, which in turn empties itself in the Dead Sea. Although the land is arid, agriculture is possible along the wadis; in fact, the modern visitor walking from the road to the fort will cross some fields in a shallow valley. The fort itself rises above this depression, and its towers dominate the plain.

If the Romans wanted to observe and control the local nomads, this place was almost perfect, and it comes as no surprise that they were not the first to occupy this place. In the neighborhood are two towers from the Iron Age, called Qasr el-Al and Qasr Abu el-Kharaq, which were reused by Nabataean soldiers. The fort itself replaced another Nabataean stronghold. There may have been an ancient road in the neighborhood, perhaps leading to the nearby legionary base at Lejjun, but the evidence consists of just one, uninscribed milestone. The road itself has not yet been identified.

The fort occupies an area of about 57 x 54 meters. The curtain walls, which survive in a nearly perfect condition, are about 1½ meters thick and 6 meters high, excluding the crenelated rampart. They connect four heavy, square corner towers, which measure 11 to 12 meters and project some three meters beyond the walls. These three-storied structures used to be more than 10 meters high. Next to the western tower was a small postern gate, less than a meter wide.

The central gate, which faces the shallow valley to the southwest, is flanked by two towers that are about half as large as the corner towers. The building inscription of the fort, a rarity in this part of the limes, survives and mentions the emperors of the First Tetrarchy:

Optimis maximisque principibus nostris Caio Aurelio
Valerio Diocletiano Pio Felici Invicto Augusto et
Marco Aurelio Valerio Maximiano Pio Felici Invicto Augusto et
Flavio Valerio Constantio et Galerio Valerio Maximiano
nobilissimis Caesaribus Castra Praetorii Mobeni fossamentis
Aurelius Asclepiades praeses provinciae Arabiae
perfici curavit

In honor of our best and greatest rulers, Gaius Aurelius Valerius Diocletian, our pious, lucky, and unconquered emperor, and Marcus Aurelius Valerius Maximian, our pious, lucky, and unconquered emperor, and to Flavius Valerius Constantius and Galerius Valerius Maximianus, our noblest caesars, has Aurelius Asclepiades, praeses of the province of Arabia, ordered to build Castra Praetorium Mobene from its foundations.^note[EDCS-29900168.]

This inscription allows us to date the construction of the fort to 293-305, when the Romans constructed more forts in this sector of the frontier. Qasr Bshir was in use throughout the fourth century and may have been abandoned in the early fifth century. It was certainly reused in the Umayyad age, because there are traces of a machicolation above the entrance, an invention commonly to postdate the Arab conquests.

The courtyard, which has two cisterns, is on all sides surrounded by rooms, twenty-three in number, which have been identified as stables. There was a second story, where the soldiers must have slept. The roof of these barracks reached the same height as the rampart walk, creating a really wide fighting platform. One room, opposite the main gate, may have been the headquarters, some kind of sanctuary, or both.

The purpose of the Castra Praetorium Mobene is a bit of a mystery. Because each of the twenty-three stables was used by three horses, and because a cavalry unit of frontier soldiers appears to have numbered between 120 and 150 men, Qasr Bshir cannot have been the base of a full-strength unit. It is remarkable that Mobene is not mentioned in the Notitia Dignitatum and that the building inscription does not refer to the name of the unit or its commander. Perhaps it was not a normal fort, but a place where the provincial governor resided when he needed to discuss matters with the nomads. (There are several tribal graffiti near the entrance.) Alternatively, the castle was used by horsemen patrolling this sector of the Roman frontier, soldiers belonging to a unit that was, according to the Notitia Dignitatum, stationed in nearby Naarsafari (modern Wadi Afaris), the Ala Secunda Miliarensis. These men may have visited Mobene during their patrols only, and may have lived somewhere else.

Qasr Bshir, Rubbish at the court	Qasr Bshir, Court	Qasr Bshir, Rubbish at the court	Qasr Bshir, Sanctuary
Qasr Bshir, Southern tower	Qasr Bshir, View from the outside	Qasr Bshir, Curtain wall	Qasr Bshir, Cistern