After Manzikert, the Byzantine government sent a new army to contain the Seljuk Turks under Isaac Komnenos, a brother of the future emperor Alexios I Komnenos, but this army was defeated and its commander captured in 1073. The problem was made worse by the desertion of the Byzantines' western mercenaries under Roussel de Bailleul who were setting up an independent principiality in the region of Galatia and Lycaonia. They became the object of the next military expedition in the area, led by Michael's uncle, Caesar John Doukas. This campaign also ended in failure, and John was likewise captured by the enemy. The victorious Roussel now forced John Doukas to stand as pretender to the throne and sacked Chrysopolis, just opposite Constantinople. The government of Michael VII was forced to recognize the conquests of the Seljuks in Asia Minor in 1074, and to seek their support. A new army under Alexios Komnenos, reinforced by Seljuk troops sent by Malik Shah I, finally defeated the mercenaries and captured John Doukas in 1074.