John of Brienne

John of Brienne (1148-1237), Latin king of Jerusalem (1210-1225). John, a French nobleman, became king by his marriage to Queen Marie de Montferrat of Jerusalem. When Marie died, their young daughter Yolande succeeded as queen under John's regency. After playing an important part in the Fifth Crusade, John lived and traveled in western Europe, seeking support for another Crusade. In 1222 he betrothed Yolande to the Holy Roman emperor Frederick II. Upon their marriage in 1225, Frederick quickly claimed the crown of Jerusalem. John, also claiming the crown, commanded papal troops in an attack upon Frederick's possessions in Italy. In 1229 John became regent and coemperor with Baldwin II, the 12-year-old Latin ruler of Constantinople (present-day İstanbul). In this capacity, he defended the Latin Empire against attacks by the Byzantines and their Bulgarian allies.