The anti-imperial alliance formed by the cities of Lombardy: Bergamo, Brescia, Mantua, Ferrara, and Verona; Vicenza, Padua, and Treviso belonging to an earlier league, with Pope Alexander III against the Emperor Frederick I.
A fortress was built called Alessandria, and a great victory won by the League at Legnano, 1176.
In the treaty of Venice, 1177, Frederick recognized Alexander as pope, which was the defeat of his pretensions to rule Italy and to interfere with papal elections.
The League was renewed, 1226, against Frederick II; the struggle ended with the death of Frederick and the overthrow of the Hohenstaufens, 1250.
New Catholic Dictionary