Popes and Emperors 453 In his lifelong attempt to maintain what he thought to be his rights as Emperor he met, quite naturally, with the three old difficulties. He had constantly to be fighting his rivals and rebellious vassals in Germany ; he had to face the opposition of the popes, who never forgot the claims that Gregory VII had made to control the Emperor as well as other rulers. Lastly, Frederick's difficulties Fig. 169. Ruins of Barbarossa's Palace at Gelnhausen Frederick Barbarossa erected a handsome palace at Gelnhausen (not far east of Frankfort). It was destroyed by the Swedes during the Thirty Years' War (see below, section 113), but even what now remains is imposing, especially the arcade represented in the picture in trying to keep hold of northern Italy, which he believed to belong to his empire, he spent a great deal of time with but slight results. One of the greatest differences between the early Middle Ages and Frederick's time was the development of town life. Up to this period we have heard only of popes, emperors, kings, bishops, progi"^3s and feudal lords. From now on we shall have to take the towns and their citizens into account. No nation makes much progress Importance of the towns in human
