Lombard League, a medieval coalition of northern Italian cities. The league was formed in 1167 when the Holy Roman Emperor Frederick I (Barbarossa) prepared to conquer the cities of Lombardy. Milan, Parma, Padua, Cremona, Mantua, Verona, Piacenza, and Bologna were among the leading members. Pope Alexander III became their leader. Frederick was defeated at Legnano in 1176. The league was renewed in 1226 to combat Frederick II.