support they needed to subdue rebellious dukes. In time, however, the Church came to regret this close relationship. The alliance broke down in 1075 during what came to be known as the Investiture Controversy (or Investiture Dispute), a struggle in which the reformist Pope, Gregory VII, demanded that Emperor Henry IV renounce his rights over the Church in Germany. The pope also attacked the concept of monarchy by divine right and gained the support of significant elements of the German nobility interested in limiting imperial absolutism. More importantly, the pope forbade ecclesiastical officials under pain of excommunication from supporting Henry as they had so freely done in the past. In the end, Henry IV journeyed to Canossa in northern Italy in 1077 to do penance and to receive absolution from the pope. However, he resumed the practice of lay investiture (appointment of religious officials by civil authorities) and arranged the election of an antipope (Antipope Clement III) in 1080. The monarch's struggle with the papacy resulted in a war that ravaged through the Holy Roman Empire from 1077 until the Concordat of Worms in 1122. The reign of the last ruler of the Salian dynasty Henry V coincided with the final phase of the great Investiture Controversy, which had pitted pope against emperor. By the settlement of the Concordat of Worms, Henry V surrendered to the demands of the second generation of Gregorian reformers. This agreement stipulated that the pope would appoint high church officials but gave the German king the right to veto the papal choices. Imperial control of Italy was lost for a time, and the imperial crown became dependent on the political support of competing aristocratic factions. Feudalism became more widespread as freemen sought protection by swearing allegiance to a lord. These powerful local rulers, having thereby acquired extensive territories and large military retinues, took over administration within their territories and organized it around an increasing number of castles. The most powerful of these local rulers came to be called princes rather than dukes. According to the laws of the feudal system of the Holy Roman Empire, the king had no claims on the vassals of other princes, only on those living within his family's territory. Lacking the support of the formerly independent vassals and weakened by the increasing hostility of the Church, the monarchy lost its pre-eminence. Thus the Investiture Contest strengthened local power in the