188 THE LATER MIDDLE AGES most serious form was brought to an end by the agreement of 1 1 22 called the Concordat of Worms, whereby it was settled that ecclesiastical dignitaries should be chosen by the cathedral chapters, that is, the clergy definitely associated with the cathedrals, and should be invested with ecclesiastical authority by the Church; but that they should also do homage to the emperor or king for the temporalities, in effect the land held by them from him as his vassals. On Henry's death he left no son, and his nominee as successor, Frederick of Swabia, was rejected in favour of Tne Swabian Lothair of Saxony. On his death, however, Conrad Line - of Swabia was elected German king; and from this period dates the rivalry of the Swabian house of Hohen- staufen and the Saxon house of the Welfs or Guelfs, the rivalry between the Guelfs and Ghibellines. The name Ghibelline is the Italian corruption of Waiblingen, which, like Hohenstaufen, was a place-name of the Swabian house. The name Hohenstaufen, however, is the one usually appropriated to the dynasty. Conrad was never crowned emperor. He was much occupied with the antagonism of the rival Saxon house, and took a reluctant and far from successful part in the ignominious second crusade. On his death the election fell not on his son, but on his nephew Frederick, known as Barbarossa, whose mother 2 Frederick was a Guelf. Frederick's first concern was with Barbarossa, Italy. He entered the peninsula primarily with H52-1190. faQ intention of lowering the pride of the great city of Milan. His arms were immediately successful, and he withdrew again after receiving the Imperial Crown from Pope Hadrian iv., the only Englishman who has ever occupied the papal chair. But he very soon found himself obliged to return. As a general rule in Europe during the Middle Ages our attention is attracted to the power of great nobles acting Cities of perpetually so as to prevent the Crown from Germany acquiring an effective supremacy. But beside and Italy. fae power of the nobles, we find in Germany that certain great cities achieved a power which gave them the
