The evidence suggests that in Taraz, as other cities in Southern Kazakhstan, Turks were the major ethnic element of the population in 4th-13th centuries, together with Sarts, Arabs and Persians . Written sources of Paleo-Anthropological material collected from Kurgans in Southern Kazakhstan show the existence of close ties between Taraz and the Kypchaks, Qarluq populations of nearby valleys. As a result of an internecine struggle amongst Turkish tribal leaders at the beginning of the 8th century the Turkish tribe in the Ili River Valley was divided into two branches: Yellow and Black. The Black(Kara) Turkish owned the Talas River Valley and made Taraz their capital in the middle of the 7th century. In 751 in the Talas River region, upstream from the modern city of Taraz, an army comprising Tang Dynasty troops from China and Kara Turkish mercenaries fought an army from the Abbasid Caliphate. Despite winning the battle, the Caliphate forces withdrew from the region. In 766 the Kara-Turkish tribes were defeated by Qarlugs from the northwest. Later, nearly all the tribes of the former Western Turk Khanate were conquered.