of the revolutionary spirit narrowed the field of contention, and the question became merely one of fixing the limits of this or that territorial State and of locating the frontier between the two established forms of religion.
Yet peace was not any nearer because the rivals had beaten a common foe. The agreement of Nürnberg in 1532 had guaranteed to the members of the Schmalkaldic League immunity for their religion, but it did not define religion or provide security for future Protestants. At the Peace of Cadan in 1534 the first point was settled by Ferdinand's quashing all the processes in the Reichskammergericht against the Schmalkaldic allies; but the protection did not extend beyond the members of the League, and numerous other Protestant States were liable to practical ruin as the result of the Supreme Court's verdicts. This was a particularly dangerous cause of friction, because Catholic Princes had other than religious motives for executing the judgments of the Court against their Protestant neighbours; as executors of the Court's decrees they could legally seize the lands of recalcitrant cities or lords, and under the guise of religion extend their territorial power. Thus, Duke Eric of Brunswick-Calenberg was anxious to execute sentence on his chief town, Hanover, where a revolutionary movement had taken place; the Duke of Bavaria cast longing eyes on Augsburg; and the specific object of the Catholic League of Halle (1533) was to secure the execution of verdicts against all cities and Princes who were not among the Schmalkaldic confederates. The Catholics undoubtedly had the law on their side, but necessity drove their opponents to break it. They could hardly stand by while their fellow-countrymen were punished for holding the faith they held themselves; had they done so they would only have prepared the way for their own destruction. The obvious method of protecting their co-religionists was to admit them to the Schmalkaldic League; but this was an infraction of the terms of the Nürnberg Peace which would endanger their own security, and they would not have ventured on the step unless circumstances had tied the hands of the Austrian government.
Throughout the greater part of 1535 Charles V was engaged in the conquest of Tunis, and he was hoping to follow up his success in this direction with an attack on the Turks, who were embroiled in a war with Persia, when his plans were disconcerted by the hostile attitude of France. Francesco Sforza, Duke of Milan, died in 1535 without issue, and Francis I, fearing with good reason that Charles would seize the duchy himself, revived his claims to Milan, Genoa, and Asti. In the spring of 1536 he overran Savoy, which had become the Emperor's ally, entered into negotiations with the Turks and with Henry VIII for a joint action against the Habsburgs, and approached the Lutheran Princes with a similar object. The Lutherans were reluctant to side with the Emperor's enemies, but they had no hesitation in putting a high price on their friendship, and in turning Charles' necessities to
