1911 Encyclopædia Britannica/Yolande of Brienne

YOLANDE [or Isabella] OF BRIENNE (1212–1228), the daughter of John of Brienne, who had married Mary, daughter of Conrad of Montferrat, heiress on the death of Amalric II. of the kingdom of Jerusalem. Yolande inherited the throne on her mother's death in 1212, but her father ruled as her guardian. In 1223 she married the emperor Frederick II., the pope hoping by this bond to attach the emperor firmly to the crusade. Immediately upon his marriage Frederick demanded all the rights of sovereignty in the kingdom of Jerusalem, which he claimed to exercise in his wife's name. His action led to difficulties with John, who did not relish the loss of his position. Yolande died in 1228 after the birth of a son, Conrad, and her husband then continued to rule, though not without opposition.