Ahmad Sanjar
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.