Limes Arabicus

The Limes Arabicus was a desert frontier of the Roman Empire, mostly in the province of Arabia Petraea. It ran northeast from the Gulf of Aqaba for about 1,500 kilometers (930 mi) at its greatest extent, reaching northern Syria and forming part of the wider Roman limes system. It had several forts and watchtowers.

The reason of this defensive "Limes" was to protect the Roman province of Arabia from attacks of the "barbarian" tribes of the Arabian desert. The main purpose of the Limes Arabicus is disputed; it may have been used both to defend from Saracen raids and to protect the commercial lines from robbers.

Next to the Limes Arabicus Emperor Trajan built a major road, the Via Nova Traiana, from Bosra to Aila on the Red Sea, a distance of 267 miles/430 kilometres. Built between 111 and 114 AD, its primary purpose may have been to provide efficient transportation for troop movements and government officials as well as facilitating and protecting trade caravans emerging from the Arabian Peninsula. It was completed under Emperor Hadrian.

During the Severan dynasty (AD 193–235), the Romans strengthened their defences on the Arabian frontier. They constructed several forts at the northwest end of the Wadi Sirhan, and improved the roads. One important fort was Qasr Azraq, another was at Humeima (Latin: Auara), from the late 2nd C AD, on the Via Nova from Petra to Aila, where up to 500 auxiliary troops could have resided. It was probably abandoned in the fourth century.

Emperor Diocletian partitioned the old province of Arabia by transferring the southern region to the province of Palaestina. Later in the 4th century, Palaestina was made into three provinces, and the southern one was eventually called Palaestina Tertia. Each province was administered by a praeses with civil authority and a dux with military authority.

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