Andronicus I Comnenus (b. 1118, Constantinople - d. 12 Aug 1185, Constantinople), Byzantine emperor from 1183 to 1185, the last of the Comnenus dynasty, who attempted to reform the government but whose bitter opposition to Western Christianity precipitated a Norman invasion.
A cousin of the Emperor Manuel I, Andronicus opposed the unpopular regency of the dowager empress Mary of Antioch after Manuel's death. In the spring of 1182 he raised an army and entered Constantinople posing as the protector of the young emperor Alexius II; one of the results of his seizure of power was a massacre of the Westerners living in the city, mostly Venetians and Genoese. Soon after, he contrived the death of the Dowager Empress. In Sep 1183 he was crowned coemperor to Alexius and 2 months later had him strangled. To legitimize his usurpation, the 65 year old Andronicus married Alexius' 13 year old widow. [Encyclopaedia Britannica]