There followed the rule of the Ottonian dynasty of Germany. During the reign of Henry V began a long war over the succession to the bishop of Como between Milan, supporting a bishop imposed by the German Emperor, and Como, which had already designated as bishop Guido Grimoldi, consecrated by the Pope. The war lasted ten years (1117–1127), with a series of small victories and defeats on land and water. Bellagio participated with its fleet as an ally of Milan, Isola Comacina and Gravedona. The war ended with the destruction of Como and its subjection to Milan, from which it took decades to recover. It is thought that by 1100 Bellagio was already a free commune and seat of a tribunal and that its dependence on Como was merely formal. However the strategic position of Bellagio was very important for the city of Como, and Bellagio had therefore to suffer more than one incursion from Como and fought numerous naval battles against its neighbour. In 1154, under Frederick Barbarossa, Bellagio was forced to swear loyalty and pay tribute to Como.