The oasis towns on the Silk Roads in Central Asia had once been controlled by the Türgesh, but the Turkic tribal confederation plunged into chaos in the latter half of the 7th century. The Tang empress Wu had retaken control of the Tarim Basin from the Tibetan Empire in 692 as part of the Tang expansion in Inner Asia and the oasis towns became a major source of income for the Chinese Tang dynasty. In 705 Qutayba ibn Muslim started to lead the army of the Arab Umayyad caliphate into wars to conquer Silk Road towns, exploiting Türgesh infighting. The Umayyad conquered the oasis towns Bukhara and Samarqand, expanding the border of their empire eastwards. At the same time the Türgesh khagan tribe leader Suluk began uniting the infighting Türgesh tribes. The Umayyad Arab, Tibetan and Tang armies would have two encounters. In 715 Alutar was established as king of Fergana with the help of Umayyad and Tibetan soldiers. The disposed Ikhshid fled to the Tang controlled Kuqa, requested the aid of the emperor Xuanzong of Tang and 10,000 Tang soldiers reinstated Ikhshid as Fergana king. In 717 Arab Umayyad soldiers, assisted by the Tibetan Empire, besieged the oasis town Aksu in the Tarim Basin, but were defeated by the Tang military in the battle of Aksu.