An official whose personality dominated politics for the greater part of the eleventh century. He was the only brother of emperor Constantine X Doukas (1059-1067) and in 1057 he supported the coup that overthrew Michael VI (1056-1057) and elevated Isaakios I Komnenos (1057-1059) to the imperial throne. During the reign of Constantine X Doukas he was honored with the title of caesar. In 1067 he supported the rise of Romanos IV Diogenes to the throne, while in 1071 he instigated another coup that proclaimed Michael VII Doukas emperor. In 1073, commanding an army, he unsuccessfully faced the Frankish rebel Ursel de Bailleul near Dorylaion, while in 1081 he contributed to the rise of Alexios I Komnenos to the throne.