point Henry made common cause with the majority of his bishops and withdrew his obedience from Gregory at the Diet of Worms in January 1076. The ensuing conflict was a landmark in the history of the papacy. Gregory excommunicated Henry and urged his subjects to force him to subjection, and eventually he recognized a German prince, Rudolf of Rheinfelden, as king. For his part Henry, after a brief period of reconciliation achieved under pressure at the famous meeting at Canossa in 1077, campaigned successfully to replace Gregory by a more pliable pope and refused to recognize Gregory's reforming successors. When he died in 1106 he was still excommunicate.
The conflict generated an immense pamphlet literature from the advocates of both sides. In the course of this, issues which had been peripheral became central, and at the heart of these was the question of the rights which kings might exercise within their churches. From the early eleventh century kings had begun to invest prelates with a ring and staff, symbolizing both the office which was being given and the estates of the Church. In the event of a chapter presenting an unwelcome candidate, the final word lay with the king, who could block the appointment by withholding investiture. Gregory himself had attempted to prevent Henry from following this custom, and his successors, Popes Urban II ( 1088-99) and Paschal II ( 1099-1118) had a series of decrees passed which were intended to ban the practice everywhere. They did so on theological rather than political grounds. Hands which consecrated the Eucharist risked contamination when joined with those of men who handled swords, and on the same grounds they prohibited the clergy from doing homage to laymen. The principle that kings could dispense ecclesiastical office was thus effectively rejected. At the same time it came to be accepted that a king, though able to provide an essential support to the Church in resisting the encroachment of the local nobility, was as liable as they to excommunication if he turned his authority to more oppressive uses. Eventually, in agreements reached with the English and French monarchies in 1106-7, and with the German monarchy in the Concordat
-133-