Bertha-Irene of Sulzbach, first wife of Manuel I Comnenus

Abstract

From the time of the Norman conquest in 1071 of Bari, the last Byzantine possession in Italy, and Robert Guiscard's invasions of Greece in the 1080s, the Normans had been a constant threat to the Byzantine empire. As a result, the foreign policy of both John II (1118-1143) and Manuel I Comnenus (1143-1180) was motivated by the desire to ally themselves with Germany in order to neutralise the threat of the Normans, an alliance which was pursued until the Byzantine defeat at Brindisi in 1156, when it was terminated by Frederick I Barbarossa for having outlived its usefulness. In the circumstances, John II (1118-1143) considered that a marriage alliance with Germany would be prudent, and he fixed on his youngest son Manuel as the most suitable candidate for such an alliance, perhaps because of his Latin sympathies: earlier John had considered marrying Manuel to Constance, the only daughter of the prince of Antioch. She was, however, quickly married to Raymond of Poitiers in 1136 to avoid Antioch coming under Byzantine control.