Charles, notwithstanding his victory at Pavia, did not invade France, but, as the price of freedom, he prescribed the harshest conditions to the captive king. At first they were rejected, but his haughty spirit and conscience were at length both reconciled to the casuistry that the fulfilment of forced promises may be eluded. Francis, therefore, consented to the treaty of Madrid, made in 1526, by which it was stipulated that he should give up his claims in Italy and the Low Countries; surrender the Duchy of Burgundy to Spain; and return into captivity if these conditions were not fulfilled in six weeks. When once at large, instead of executing the treaty, he formed a league with the Pope, the King of England, and the Venetians, to maintain the liberty of Italy. The Pope absolved him from his oaths, and he refused to return into Spain. The passions of the rival monarchs were now much excited, and challenges and the lie were exchanged between them. No duel was fought, nor probably intended; but the notoriety of the challenge went far to establish a false point of punctilio, we will not call it honor, among gentlemen, and single combats became more frequent than in the ages of barbarism. In 1529, the course of these calamities was suspended by the treaty of Cambray, negotiated in person by two women. The Duchess of Angouleme and Margaret of Austria, governess of the Low Countries, met in that city, and settled the terms of pacification between the rival monarchs. For Charles's honorable conduct on Luther's appearance before the diet of Worms, the reader may refer to the life of the reformer in the present volume. The cause of Lutheranism gained ground at the diet of Nuremberg; and if Charles had declared in favor of the Lutherans, all Germany would probably have changed its religion. As it was, the Reformation made progress during the war between the emperor and Clement VII. All that Charles acquired from the diet of Spire, in 1526, was to wait patiently for a general council, without encouraging novelties. In 1530, he assisted in person at the diet of Augsburg, when the Protestants (a name bestowed on the reformers in consequence of the protest entered by the Elector of Saxony and others at the second diet of Spire) presented their confession, drawn up by Melancthon, the most moderate of Luther's disciples. About this time Charles procured the election of his brother Ferdinand as king of the Romans, on the plea that, in his absence, the empire required a powerful chief to make head against the Turks. This might be only a pretence for family aggrandizement; but the emperor became seriously apprehensive lest the Lutherans, if provoked, should abandon the cause of Christendom, and policy therefore conceded what zeal would have refused. By a treaty concluded with the Protestants at Nuremberg, and ratified at Ratisbon in 1531, Charles granted them liberty of conscience till a council should