 Complete the following phrase:  The struggle between Guelphs and Ghibellines was a feature of Parma too. In 1213, her podestà was the Guelph Rambertino Buvalelli. Then, after a long stance alongside the emperors, the Papist families of the city gained control in 1248. The city was besieged in 124748 by Emperor Frederick II, who was however crushed in 