Atsïz gained his position following his father's death in 1127 or 1128. During the early part of his reign, he focused on securing Khwarazm against nomad attacks. In 1138, he rebelled against his suzerain, the Seljuk Sultan Ahmad Sanjar, but was defeated in Hazarasp and forced to flee. Sanjar installed his nephew Suleiman Shah as ruler of Khwarazm and returned to Merv. Atsïz returned, however, and Suleiman Shah was unable to hold on to the province. Atsïz then attacked Bukhara, but by 1141 he again submitted to Sanjar, who pardoned him and formally returned control of Khwarazm over to him.
