The effect of the change from the passive endurance of Ferdinand to the active vigour of Maximilian was immediately perceptible. His first object was to gain over or neutralize the German Protestants, and events in the East were seconding him to a marvel. About one-fifth only of Hungary was in Ferdinand's possession. The rest was about equally divided between the Turks and Bethlen Gabor, the Protestant Prince of Transylvania, a semi-barbarous but energetic chieftain, who hoped, with Turkish support, to make himself master of all Hungary, if not of Austria as well. In the first days of November, his hordes, in friendly alliance with the Bohemians, were burning and plundering round the walls of Vienna. But such armies as his can only support themselves by continuous success; and Bethlen Gabor found the capture of Vienna as hopeless in the winter as Thurn had found it in the summer. Retiring eastwards, he left behind him a bitter indignation against those who had abetted his proceedings, and who had not been ashamed, as their adversaries declared, to plant the Crescent upon the ruins of Christianity and civilization. [Sidenote: § 4. The Union refuses to support Frederick.] Such declamation, overstrained as it was, was not without its effect. German Protestantism had no enthusiasm to spare for Frederick's enterprise in Bohemia. At a meeting of the Union at Nüremberg, Frederick's cause found no support. Maximilian could well afford to leave the Union to its own hesitation, and to think only of conciliating the Elector of Saxony and the North German princes. [Sidenote: 1620. § 5. The agreement of Mühlhausen.] That John George should have taken serious alarm at his rival's increase of power is not surprising. Not only did it assail whatever shadow still remained of the protecting institutions of the Empire, but it did so in a way likely to be especially disagreeable at Dresden. The revolution at Prague did not simply raise an otherwise powerless person into Ferdinand's place. It gave the crown of Bohemia to a man whose territories were already so extensive that if he managed to consolidate his new dominion with them he would unite in his hands a power which would be unequalled in the Empire, and which would bring with it the unheard-of accumulation of two votes upon one person at imperial elections. John George would descend from being one of the first of the German princes to a mere second-rate position. [Sidenote: § 6. The ecclesiastical lands held by Protestants guaranteed under conditions.] John George was not to be won for nothing. At an assembly held at Mühlhausen in March 1620, the League promised that they would never attempt to recover by force the lands of the Protestant administrators, or the secularized lands in the northern territories, as long as the holders continued to act as loyal subjects; and this promise was confirmed by the Emperor. [Sidenote: § 7. Spinola prepares to attack the Palatinate.]