Wars of the Guelphs and Ghibellines: Troops of the Lombard League defeated forces of the Holy Roman Empire at the Battle of Legnano in present-day Italy. Battle of Legnano: The Battle of Legnano was fought on 29 May 1176 between the army of Frederick Barbarossa, Holy Roman Emperor, and the forces of the Lombard League near Legnano, between Milan and Como, in the Kingdom of Italy. It was the climactic field engagement of Frederick's fifth Italian campaign and one of the most consequential battles of the long conflict between the emperor, the northern Italian communes and Pope Alexander III. The encounter itself arose unexpectedly from manoeuvres by two armies that were aware of one another but did not possess precise information about the other's position. Frederick was attempting to move from Como towards the security of Pavia, where he could join additional imperial and Italian forces, while the League sought to intercept him before such a concentration could occur. May 29, 1176. Wiki link