The Qahtanite Arabs are the southern Arabian tribal groups claiming descent from Qahtan (identified with the biblical Joktan, son of Eber — Genesis 10:25-29), making them a distinct Semitic lineage from the Adnanite (Ishmaelite) line. The Qahtanites built the great pre-Islamic South Arabian civilizations: the Sabaean kingdom (home of the Queen of Sheba), the Minaean, Qatabanian, and Hadramawt kingdoms. Their agricultural civilization — sustained by the famous Ma’rib Dam — supported a sophisticated urban culture. The collapse of the Ma’rib Dam (~570 AD) triggered the migration of Qahtanite tribes northward into the Hijaz and beyond, directly reshaping the demographic and political landscape into which Islam emerged. The Aws and Khazraj tribes of Medina — who welcomed Muhammad in the Hijra — were Qahtanite Arabs.