Byzantium's relations with the Normans of Antioch and Italy, although the other formidable powers of the age in the Balkans, in West and East were also involved. Sustained diplomatic activity (mainly with the West) led to the creation of a web of alliances which was continuously changing in the attempt to strike a balance of power.The Emperor tried to enter into alliance with Germany against the Normans. His attempt, however, did not yield the required results, due to the Second Crusade (1147-48), in which the German Emperor participated as well. Only after the miscarriage of the crusade did the rapprochement of Byzantium with Germany became possible. Byzantium had also allied with Venice against the Normans (1148), who, in the meanwhile, had invaded Byzantine territory occupying Corfu, Corinth and Thebes (1147). The cooperation with the Germans came to an end when Frederick I (1152-90) ascended the throne (he was hostile towards Byzantium) and with the Venetians when the Byzantines re-occupied certain parts of Italy (1155) that threatened Venetians interests.
The successes of Manuel's policy included the definitive subjugation of the Latin hegemony in Antioch (1159), his successive interventions in Hungary and the submission of Stephen Nemanja of Serbia (1172). These successes, however, were temporary since the Empire was no longer in a position to hold on to these territories. Manuel's ambitious but unrealistic policy is illustrated by the defeat by the Turks at Iconium, Myriokephalon in 1176.