How genuinely popular was the Lutheran movement may be seen in the fact that the free cities, Nuremberg, Augsburg, Strassburg, Ulm, Luebeck, Hamburg, and many others were the first to revolt from Rome. In other states the government led the way. Electoral Saxony evolved slowly into complete Protestantism. Though the Elector Frederic sympathized with almost everything advanced by his great subject, he was too cautious to interfere with vested interests of ecclesiastical property and endowments. On his death [Sidenote: May 5, 1525] his brother John succeeded to the title, and came out openly for all the reforms advocated at Wittenberg. The neighboring state of Hesse was won about 1524, [Sidenote: 1424-5] though the official ordinance promulgating the evangelical doctrine was not issued until 1526. A very important acquisition was Prussia. [Sidenote: 1525] Hitherto it had been governed by the Teutonic Order, a military society like the Knights Templars. Albert of Brandenburg became Grand Master in 1511, [Sidenote: Albert of Brandenburg, 1490-1568] and fourteen years later saw the opportunity of aggrandizing his personal power by renouncing his spiritual ties. He accordingly declared the Teutonic Order abolished and himself temporal Duke of Prussia, shortly afterwards marrying a daughter of the king of Denmark. He swore allegiance to the king of Poland. The growth of Lutheranism unmolested by the imperial government was made possible by the {114} absorption of the emperor's energies in his rivalry with France and Turkey and by the decentralization of the Empire. [Sidenote: Leagues] Leagues between groups of German states had been quite common in the past, and a new stimulus to their formation was given by the common religious interest. The first league of this sort was that of Ratisbon, [Sidenote: 1524] between Bavaria and other South German principalities; its purpose was to carry out the Edict of Worms. This was followed by a similar league in North Germany between Catholic states, known as the League of Dessau, [Sidenote: 1525] and a Protestant confederation known as the League of Torgau. [Sidenote: The Diet of Spires, 1526] The Diet held at Spires in the summer of 1526 witnessed the strength of the new party, for in it the two sides treated on equal terms. Many reforms were proposed, and some carried through against the obstruction by Ferdinand, the emperor's brother and lieutenant. The great question was the enforcement of the Edict of Worms, and on this the Diet passed an act, known as a Recess, providing that each state should act in matters of faith as it could answer to God and the emperor. In effect this allowed the government of every German state to choose between the two confessions, thus anticipating the principle of the Religious Peace of Augsburg of 1555.