Arabia Petraea or Petrea, also known as Rome's Arabian Province (; ; ) or simply Arabia, was a frontier province of the Roman Empire beginning in the 2nd century. It consisted of the former Nabataean Kingdom in Jordan, southern Levant, the Sinai Peninsula and northwestern Arabian Peninsula. Its capital was Petra. It was bordered on the north by Syria, on the west by Judaea (merged with Syria from AD 135) and Egypt, and on the south and east by the rest of Arabia, known as Arabia Deserta and Arabia Felix. The territory was annexed by Emperor Trajan, like many other eastern frontier provinces of the Roman Empire, but held onto, unlike Armenia, Mesopotamia and Assyria, well after Trajan's rule, its desert frontier being called the Limes Arabicus. It produced the Emperor Philippus, who was born around 204. As a frontier province, it included a desert populated by Arabic tribes, and bordering the Parthian hinterland. Though subject to eventual attack and deprivation by the Parthians and Palmyrenes, it had nothing like the constant incursions faced in other areas on the Roman frontier, such as Germany and North Africa, or the entrenched cultural presence that defined the other more Hellenized eastern provinces. Geography The geographic makeup of Arabia has some variation. It includes the comparatively fertile Moab plateau, which received 200mm of annual rainfall, at the southernmost tip of which lies Petra which, along with Bostra (or Busra), together constitute the political foci of the province. Inhospitability is the norm, though, and along with the desert proper that is the Sinai, the arid Negev, which extends north of the Sinai, is practically such. Along with this are the coastal areas around the Red Sea; the badlands known as Hismā that develop to the north of that coast; and the ever-present rocky terrain. Major cities Most of Arabia was sparsely populated, and its cities can be found concentrated to the north, toward the Jordan. The only major port is Aqaba, at the tip of the wide Gulf of Aqaba, a branch of the Red Sea. In AD 106, when Aulus Cornelius Palma Frontonianus was governor of Syria, the part of Arabia under the rule of Petra was absorbed into the Roman Empire as part of Arabia Petraea, and Petra became its capital. Petra declined rapidly under Roman rule, in large part from the revision of sea-based trade routes. In 363, an earthquake destroyed