In 1153, the Ghuzz (Oghuz Turks) rebelled and captured Sanjar. He managed to escape after three years but died a year later. The atabegs, such as the Zengids and Artuqids, were only nominally under the Seljuk Sultan, and generally controlled Syria independently. When Ahmad Sanjar died in 1157, this fractured the empire even further and rendered the atabegs effectively independent. On other fronts, the Kingdom of Georgia began to become a regional power and extended its borders at the expense of Great Seljuk. The same was true during the revival of the Armenian Kingdom of Cilicia under Leo II of Armenia in Anatolia. The Abbasid caliph An-Nasir also began to reassert the authority of the caliph and allied himself with the Khwarezmshah Takash.