John Doukas

John Doukas (died c. 1088), son of Andronikos Doukas and elder brother of Constantine X, was a general made caesar by his brother. After Constantine's death in 1067 he championed his nephew Michael VII and opposed Romanos IV Diogenes, and was forced to retire to Bithynia for much of Romanos's reign.

Following Manzikert in 1071 he returned to court and forced the empress Eudokia into a nunnery. He sent his sons to capture Romanos and ordered him blinded, securing Michael's sole rule. Ousted by the eunuch Nikephoritzes around 1073, he helped his grandson-in-law Alexios I Komnenos seize the throne in 1081.