Such a peace failed to settle the vital question as to whether in future the Protestant princes could make further confiscations, on the plea of the conversion of Catholic bishops and abbots or otherwise. As the century wore on, accordingly, the princes "secularized" many more Church estates; and as Protestantism was all the while losing moral ground in Germany through the adoption of Calvinism by several princes, and the bitter quarrels of the sects and sub-sects, the Catholics held the more strongly to their view of the Augsburg treaty, which was that all bishoprics and abbeys held directly from the emperor were to remain Catholic. Friction grew from decade to decade, and, civic wisdom making no progress on either side, a number of the Lutherans and Calvinists at length formed (1608) a militant union, led by the Calvinist prince Christian of Anhalt, to defend their gains; and the Catholics, led by Maximilian, Duke of Bavaria, formed another. The Calvinists were the chief firebrands; and Christian was bent on aggression, to the end of upsetting the power of the Catholic House of Austria. The train, however, was fired from Bohemia, where the Protestant nobles were at odds with their two successive kings, Matthias and Ferdinand, both of that house, and both bent on putting down Protestantism on the crown lands. The nobles began a revolt in a brutally lawless fashion; and when, in a winter pause of the war, Ferdinand was elected emperor (1619), they deposed him from the throne of Bohemia, and elected in his place the Calvinist prince Frederick, Elector Palatine (son-in-law of James I of England), who foolishly accepted. The capable Maximilian, with Tilly for general, took the field on behalf of Ferdinand; the Lutheran princes stood aloof from Frederick, who for his own part had offended his Lutheran subjects by slighting their rites; his few allies could not sustain him, and he was easily defeated and put to headlong flight. At once the leading Protestant nobles of Bohemia were put to death; their lands were confiscated; the clergy of the chief Protestant body, the Bohemian Brethren, dating back to the time of Huss, were expelled in mass; and Protestantism in Bohemia was soon practically at an end. Many of both the Lutheran and Calvinist churches, in their resentment at the slackness of the German Protestant League, voluntarily went over to Catholicism. At the same period the Protestant Prince of Transylvania had been in alliance with the Turks to attack Vienna; and the Protestant faith was thus discredited on another side.