The siege of Crema was a siege of the town of Crema, Lombardy by the Holy Roman Empire from 2 July 1159 to 25 January 1160. The Cremaschi attempted to defend their city from the Germans, but were eventually defeated by Frederick Barbarossa's men. Frederick seized Milan in 1162, shortly after he took Crema. These events started the wars of Guelphs and Ghibellines, leading to the formation of the Lombard League, a league of northern Italian communes allied against the emperor, supported by the Pope.