There were castra every with the purpose to create a line of protection and control: in the south there was the legionary fortress at Adrou (Udruh), just east of Petra. It probably housed the Legio VI Ferrata, which was moved from Lajjun (in modern-day Israel) by Diocletian. It is similar to Betthorus (al-Lajjun in modern-day Jordan) in size () and design, and is in the plain of Moab, south of Wadi Mujib . Alistair Killick, who excavated the site, dates it to the early 2nd century, but Parker suggests a date in the late 3rd or early 4th century.