The dominance of Ghazna was curtailed, however, when the Seljuks led themselves into the western part of the region, conquering the Ghaznavid territory of Khorazm (also spelled Khorezm and Khwarazm). The Seljuks also defeated the Qarakhanids, but did not annex their territories outright. Instead they made the Qarakhanids a vassal state. The Seljuks dominated a wide area from Asia Minor to the western sections of Transoxiana in the 11th century. The Seljuk Empire then split into states ruled by various local Turkic and Iranian rulers. The culture and intellectual life of the region continued unaffected by such political changes, however. Turkic tribes from the north continued to migrate into the region during this period. The power of the Seljuks however became diminished when the Seljuk Sultan Ahmed Sanjar was defeated by the Kara-Khitans at the Battle of Qatwan in 1141.