The cities first demonstrated their increasing power during the reign of the Hohenstaufen Emperor Frederick Barbarossa (1152–1190), whose attempts to restore imperial authority in the peninsula led to a series of wars with the Lombard League, a league of northern Italian cities, most of the times headed by Milan, and ultimately to a decisive victory for the League at the Battle of Legnano in 1176, that had as its leader the Milanese Guido da Landriano, which forced Frederick to make administrative, political, and judicial concessions to the municipalities, officially ending his attempt to dominate Northern Italy. From then, Italy became a patchwork of autonomous duchies and city-states only nominally tied to the Holy Roman Empire.