Of the Roman province, under the name of Arabia and the third Palestine, the principal cities were Bostra and Petra, which dated their aera from the year 105, when they were subdued by Palma, a lieutenant of Trajan, (Dion. Cassius, l. lxviii.) Petra was the capital of the Nabathaeans; whose name is derived from the eldest of the sons of Ismael, (Gen. xxv. 12, etc., with the Commentaries of Jerom, Le Clerc, and Calmet.) Justinian relinquished a palm country of ten days' journey to the south of Aelah, (Procop. de Bell. Persic. l. i. c. 19,) and the Romans maintained a centurion and a custom-house, (Arrian in Periplo Maris Erythraei, p. 11, in Hudson, tom. i.,) at a place (Pagus Albus, Hawara) in the territory of Medina, (D'Anville, Memoire sur l'Egypte, p. 243.) These real possessions, and some naval inroads of Trajan, (Peripl. p. 14, 15,) are magnified by history and medals into the Roman conquest of Arabia.