It provided that states already Protestant should abide so, but it said nothing of the right of other states to declare themselves Protestant. Doubt however was set aside by religious zeal; new states became Lutheran, and eight great bishoprics of the north were secularized. Meanwhile the new faith was spreading fast over the dominions of the House of Austria. The nobles of their very Duchy embraced it: Moravia, Silesia, Hungary all but wholly abandoned Catholicism. Through the earlier reign of Elizabeth it seemed as if by a peaceful progress of conversion Germany was about to become Protestant. [Sidenote: The Catholic reaction.] German Catholicism was saved by the Catholic revival and by the energy of the Jesuits. It was saved perhaps as much by the strife which broke out in the heart of German Protestantism between Lutheran and Calvinist. But the Catholic zealots were far from resting content with having checked the advance of their opponents. They longed to undo their work. They did not question the Treaty of Passau or the settlement made by it; but they disputed the Protestant interpretation of its silences; they called for the restoration to Catholicism of all church lands secularized, of all states converted from the older faith, since its conclusion. Their new attitude woke little terror in the Lutheran states. The treaty secured their rights, and their position in one unbroken mass stretching across Northern Germany seemed to secure them from Catholic attack. But the Calvinistic states, Hesse, Baden, and the Palatinate, felt none of this security. If the treaty were strictly construed it gave them no right of existence, for Calvinism had arisen since the treaty was signed. Their position too was a hazardous one. They lay girt in on all sides but one by Catholic territories, here by the bishops of the Rhineland with the Spaniards in Franche Comte and the Netherlands to back them, there by Bavaria and by the bishoprics of the Main. Foes such as these indeed the Calvinists could fairly have faced; but behind them lay the House of Austria; and the influence of the Catholic revival was at last telling on the Austrian princes. In 1606 an attempt of the Emperor Rudolf to force Catholicism again on his people woke revolt in the Duchy; and though the troubles were allayed by his removal, his successor Matthias persevered though more quietly in the same anti-Protestant policy. [Sidenote: The Union and the League.]