MICHAEL VI  ., " the warlike," was already an old man when chosen by the empress Theodora as her successor shortly before her death in ro56 . He was unable to check the disaffection of the feudal aristocracy, who combined with an officer named Isaac Comnenus to depose him . After a successful battle in Phrygia, the rebels had no difficulty in dethroning Michael (1057), who spent the rest of his life in a monastery .