The emperor was compelled to appeal to the Protestant princes to cooeperate in this great emergence.

But they had more to fear from the fiery persecution of the papal church than from the cimeter of the infidel, and they refused any cooeperation with the emperor so long as the menaces of the Augsburg decrees were suspended over them.

The emperor wished the Protestants to help him drive out the Turks, that then, relieved from that danger, he might turn all his energies against the Protestants.
After various negotiations it was agreed, as a temporary arrangement, that there should be a truce of the Catholic persecution until another general council should be called, and that until then the Protestants should be allowed freedom of conscience and of worship.

The German States now turned their whole force against the Turks.

The Protestants contributed to the war with energy which amazed the Catholics.