The Nabataeans, a nomadic Arab people from north Arabia, began to settle in the Petra area from the late 7th century BC. They seem to have arrived slowly and integrated peacefully with the settled Edomites, who were, at that time, themselves in the process of migrating to a new homeland in southern Palestine.
They were no doubt attracted initially, as previous occupants had been, by the plentiful water supply and the natural defensive position of the land surrounded by mountains. By the late 4th century BC the Nabataeans were firmly established in the Petra area, though with their nomadic traditions it is unlikely that they began building until they had been settled for some time.