Crema was also allied to Milan, and this was seen as a menace of extension of the Milanese power towards Cremona and the Po River.

In a meeting held at Casale Monferrato, the Cremonesi convinced Frederick to attack Crema, an act that would also imply a menace against the rebellious Milan.

After an ultimatum sent by Frederick on 2 February 1159, asking the destruction of their walls, was refused, the Cremaschi settled into their city to hold against a siege.

[4] Milan attempted to save Crema by assaulting a nearby town, but Barbarossa drove back the Milanese.

The defenders and civilians, some of whom had died of hunger and disease, surrendered on January 25 after the imperial troops had taken control of the outer walls.