31. The Rupture Between the Pope and the Emperor.--This bold step threatened for a time to disrupt the German empire; for the princes who remained true to the old religion openly consulted together upon the advisability of taking up arms against the Lutherans; and the princes favoring the Reformers met to consider the necessity of forming an alliance to resist their enemies. In the midst of these threatening prospects an event happened which was of great advantage to the Lutheran cause, and prevented for the moment any action against them. The Emperor Charles V and Pope {219} Clement VII became open enemies. The pontiff, fearing the increasing power of Charles, had formed an alliance with Francis I, king of France, against him. This so incensed Charles that he abolished the authority of the pope in Spain, made war upon him in Italy, captured the cities of Rome, besieged the pontiff in his castle of St. Angelo, and subjected him to great indignities. 32. The Diet at Spire--1529.--The difficulties between Charles and the pope were finally settled, however, and a diet was called at Spire in 1529, in which a majority voted to deprive the princes of Germany of the right to regulate religious matters within their respective territories--a right which a diet held three years before at Spire had granted. That is, such power was granted pending the settlement of religious difficulties by a free general council.[15] The diet also declared all changes made in the public religion unlawful. This action was considered a hardship by those princes who had made such changes, and they protested against the action of the diet and appealed to the emperor.[16] It was this protest which gave to the dissenting princes, and the followers of Luther generally, the name Protestants. 33. The envoys of the dissenting princes sent to inform Charles of the stand they had taken in relation to the religious controversy in Germany were imprisoned by him, a circumstance which threatened hostility, and the Protestant princes at once took counsel for their safety and sought to form closer alliances with each other for mutual defense. Unfortunately, however, the would-be reformers of religion were not united in {220} doctrine, and the efforts of the princes at union were rendered vain by the disputes of the theologians.