The central zone includes Hejaz (or Hijaz), Nejd and El Hasa; much of it is a dry, stony or sandy steppe, with few wells or watering-places, and only occupied by nomad tribes; but the great wadis which intersect it contain many fertile stretches of alluvial soil, where cultivation is possible and which support a considerable settled population, with several large towns and numerous villages.
The capital of Islam continued indeed for a while to be Medina, but soon the Hejaz (Hijaz) and the whole of Arabia proper lay quite on the outskirt of affairs.
His chief concern was the Quraysh and, next to them, the hostile pagan Bedouin tribes of the Hijaz.