Thus Henry forced the hand of the Pope, who as a priest could not refuse his absolution to one who showed himself ready to submit to the severest possible penance for his sins. The only course open to Gregory was to accept the situation on which he had lost the hold, and to try to get some political concessions in the negotiations which must follow. The terms did not differ much from those arranged at Tribur: Henry should accept the decision of the diet of the German nobles, presided over by the Pope, as to his continued right to the crown, while if the judgment was favourable, he should implicitly obey the Pope for the future in all that concerned the Church. But, on the other hand, the papal excommunication and absolute sentence of deposition were removed, and the whole excuse for continued rebellion was thus withdrawn from his German opponents. Henry had undoubtedly been humiliated and had acknowledged the papal arbitration in Germany: but modern feelings probably exaggerate the humiliation of the penitential system, and Henry had at least divided his enemies. The Pope had undertaken to see fair play between Henry and his German subjects: the German nobles had based their action on Henry's past conduct, for which he had now done penance. Henry had obtained an acknowledgment from the Pope that his right to the kingship was at any rate an open question.
The German nobles had been betrayed by the Pope, but they could not afford to quarrel with him. They had been outwitted by Henry, and against him they proceeded as having violated the Agreement of Tribur. A Diet met at Forchheim, in Franconia, in March, 1077. It was chiefly composed of lay nobles, but papal legates were present, whom Gregory instructed to work for a postponement until he himself could come. But the nobles were determined, and Henry's brother-in-law, Duke Rudolf of Suabia, was chosen King. Gregory, however, did not intend to have his hand forced again, and for three years (1077-80) he refused to acknowledge Rudolf and tried to pose as arbiter between him and Henry. Five times Rudolf's supporters wrote remonstrating indignantly against this neutrality. Gregory excused himself on the ground that his legates had been deceived and had acted under compulsion in acquiescing in the action of the diet at Forchheim. He had good reasons for his delay. He was determined to secure recognition of the right which he claimed for the Papacy as the real determining force in the dispute, an act which the nobles had deliberately prevented. Moreover, he was a little afraid of a trial of strength with Henry at the moment. For while Henry's promptness had caused the Pope to break faith with his allies, Gregory's severity had gathered round Henry a party which made the King more powerful than he yet had been. Thus in Lombardy the Countess Matilda was faced by a revived imperialist party which seriously threatened her dominions, while in Germany the clergy, the lesser nobles and the cities rallied round the King.