Alliance of the two empires. In the first years of the reign of Manuel his western policy, like that of his predecessor, was regulated by the idea of the alliance with Germany which had been achieved under the pressure of the common danger from the growing power of the Italian Normans. The negotiations with Conrad III of Germany interrupted by the death of John were renewed. The question of the marriage of Manuel to the sister-in-law of Conrad, Bertha of Sulzbach, which had been proposed under John, was also renewed. In his letter to Manuel, Conrad wrote that this marriage should be a pledge of a permanent alliance of constant friendship, that the German sovereign promised to be a friend of the Emperor's friends and an enemy of his enemies, as well as, in case of danger to the Empire, to come to its aid not only with some auxiliary troops, but, if necessary, in person with all forces of the German state. Manuel's marriage to Bertha, who received in Byzantium the name of Irene, set a seal upon the alliance of the two empires. This alliance gave Manuel the hope of getting rid of the danger which threatened his state from Roger II. Of course, while Roger faced two such adversaries as the Byzantine and German sovereigns, he did not venture to begin war with Byzantium with his former hopes for success.
But an unexpected event suddenly destroyed Manuel's dreams and political speculations. The Second Crusade entirely changed the situation, at least for a time; it deprived Byzantium of German support and exposed the Empire to twofold danger from the crusaders and from the Normans.