The empress Theodora, the last ruler of the Macedonian dynasty, had chosen Michael, an elderly official, as her successor. On her death (August 21, 1056), Michael became emperor. His policies, however, antagonized the military leaders in Asia Minor, who proclaimed Isaac Comnenus (Isaac I Comnenus) emperor on June 8, 1057. Comnenus marched on Constantinople and defeated Michael's supporters on August 20. Michael abdicated 11 days later.