born 0441; 1170
died March 1237, Constantinople
Count of Brienne (in northeastern France) and later titular king of Jerusalem (121025) and Latin emperor of Constantinople (123137).
The penniless younger son of a French count, he married the queen of the Crusader state of Jerusalem, with the support of Phillip II, and after her death became regent for their infant daughter. He arranged a truce with Egypt (1212) and participated in the unsuccessful Fifth Crusade . In 1228 he became regent and coemperor of Constantinople, and he was crowned emperor three years later. He fended off attacks by Ivan Asen II and John III Ducas Vatatzes .