Eudocia Macrembolitissa (1021-1096), daughter of John Macrembolites, was the wife of the Byzantine emperor Constantine X, and after his death (1067) of Romanus IV. She had sworn to her first husband on his deathbed not to marry again, and had even imprisoned and exiled Romanus, who was suspected of aspiring to the throne. Perceiving, however, that she was not able to avert the invasions which threatened the eastern frontier of the empire unaided, she revoked her oath, married Romanus, and with his assistance dispelled the impending danger. She did not live very happily with her new husband, who was warlike and self-willed, and when he was taken prisoner by the Turks at the Battle of Manzikert (1071), she was compelled to vacate the throne in favor of her son Michael and retire to a convent, where she died at the age of 75.