Jun 18, 1155
Frederick IFrederick I planned to get his chief revenues from Italy. He considered Italy the center of a "holy empire," as he called it—hence the name Holy Roman Empire. Frederick's attempt to conquer northern Italy led to severe problems.
Nov 22, 1220
Fredrick IIestablish a strong, centralized state in Italy
struggled with popes
war in north italy
Otto Icrowned emporor of the Romans
protected the pope