A Diet of the empire was accordingly summoned at Spires, in order to take into consideration the state of religion, the main cause of all the disturbances in Germany. It met on the 15th of March, 1529, and the greatest address was required to prevent a civil war. All that Charles could obtain from the assembled princes was, the promise to prevent any further innovations. A decree to that effect was passed, against which, however, the followers of Luther protested, the most powerful of whom were the Elector of Saxony, the Marquis of Brandenburg, the Landgrave of Hesse, the Duke of Lunenburg, the Prince of Anhalt, and the deputies of fourteen imperial cities. This protest gave to them the name of _Protestants_--a name ever since retained. Soon after, the diet assembled at Augsburg, when the articles of faith among the Protestants were read,--known as the Confession of Augsburg,--which, however, the emperor opposed. In consequence of his decree, the Protestant princes entered into a league at Smalcalde, (December 22, 1530,) to support one another, and defend their religion. Circumstances continually occurred to convince Charles, that the extirpation of heresy by the sword was impossible in Germany, and moreover, he saw it was for his interest--to which his eye was peculiarly open--to unite all the German provinces in a vigorous confederation. Accordingly after many difficulties, and with great reluctance, terms of pacification were agreed upon at Nuremburg, (1531,) and ratified in the diet at Ratisbon, shortly after, by which it was agreed that no person should be molested in his religion, and that the Protestants, on their part, should assist the emperor in resisting the invasion of the Turks. The Germans, with their customary good faith, furnished all the assistance they promised, and one of the best armies ever raised in Germany, amounting to ninety thousand foot, and thirty thousand horse, took the field, commanded by the emperor in person. But the campaign ended without any memorable event, both parties having erred from excessive caution.
[Sidenote: Hostilities between Charles and Francis.]
Francis soon availed himself of the difficulties and dangers of his rival, formed an alliance with the Turks, put forth his old claims, courted the favor of the German Protestants, and renewed hostilities. He marched towards Italy, and took possession of the dominions of the duke of Savoy, whom the emperor, at this juncture, was unable to assist, on account of his African expedition against the pirate Barbarossa. This noted corsair had built up a great power in Tunis and Algiers, and committed shameful ravages on all Christian nations. Charles landed in Africa with thirty thousand men, took the fortress of Goletta, defeated the pirate's army, captured his capital, and restored the exiled Moorish king to his throne. In the midst of these victories Francis invaded Savoy. Charles was terribly indignant, and loaded his rival with such violent invectives that Francis challenged him to single combat. The challenge was accepted, but the duel was never fought. Charles, in his turn, invaded France, with a large army, for that age--forty thousand foot and ten thousand horse; but the expedition was unfortunate. Francis acted on the defensive with admirable skill, and was fortunate in his general Montmorency, who seemed possessed with the spirit of a Fabius. The emperor, at last, was compelled to return ingloriously, having lost half of his army without having gained a single important advantage. The joy of Francis, however, was embittered by the death of the dauphin, attributed by some to the infamous Catharine de Medicis, wife of the Duke of Orleans, in order to secure the crown to her husband. War did not end with the retreat of Charles, but was continued, with great personal animosity, until mutual exhaustion led to a truce for ten years, concluded at Nice, in 1538. Both parties had exerted their utmost strength, and neither had obtained any signal advantage. Notwithstanding their open and secret enmity, they had an interview shortly after the truce, in which both vied with each other in expressions of esteem and friendship, and in the exhibition of chivalrous courtesies--a miserable mockery, as shown by the violation of the terms of the truce, and the renewal of hostilities in 1541.