In 1156 Frederick married the heiress to Burgundy, which had slipped out of imperial control during the Investiture Controversy. He made Switzerland the strategic center of his policy, for it controlled the Alpine passes into Italy. In Swabia he tried to build a compact, well-run royal domain, but he needed the loyalty of cooperative great vassals. And in Lombardy he also needed an alliance with the communes in the towns.
Church and Society in the Medieval West
With the revival of the study of Roman law during the twelfth century went a corresponding interest among churchmen in the systematization of canonical law. As the texts of Justinian’s civil law became familiar to the students in the law schools—of which Bologna in Italy was the most important—the Bolognese monk Gratian about 1140 published the Decretum, a similar effort to codify for the first time past decrees of popes, enactments of church councils, and decisions of church fathers dating back a millennium.
The struggle originated in 1046, when the emperor Henry III found three rival popes simultaneously in office while mobs of their supporters rioted in the streets of Rome. He deposed all three. After two successive German appointees had died—perhaps by poison—Henry named a third German, Bishop Bruno of Toul, who became pope as Leo IX (r. 1049-1054). Leo was committed to the Cluniac program of monastic reform; the whole church hierarchy, he insisted, must be purged of secular influences, and over it all the pope must reign supreme.
When King Otto took the title of emperor in 962, he created for his successors a set of problems that far transcended the local problems of Germany. In the Carolingian West, emperor had come to mean a ruler who controlled two or more kingdoms but who did not necessarily claim supremacy over the whole world, as had Rome.
Conrad’s successor, the duke of Saxony, became King Henry I (r. 919-936). He and his descendants, notably Otto the Great (r. 936-973) and Otto III (r. 983-1002)— successfully combated the ducal tendency to dominate the counts and to control the church. In 939 the Crown obtained the duchy of Franconia; thenceforth, the German kings, no matter what duchy they came from, would also have Franconia as the royal domain.
As the Carolingian Empire gradually disintegrated in the late ninth and early tenth centuries, four duchies— Franconia, Saxony (of which Thuringia was a part), Swabia, and Bavaria—arose in the eastern Frankish lands of Germany. They were military units organized by the local Carolingians, who took the title of Duke (army commander).