Of course here the economic side of the question played a great part.

The ecclesiastical potentates and those favourable to them dreaded the spread of Protestantism in view of the secularization of religious domains and fiefs.

This, notwithstanding that there were not wanting bishops and abbots themselves who were not indisposed, as princes of the empire, to appropriate the Church lands, of which they were the trustees, for their own personal possessions.
After a short civil war an arrangement was come to at the Treaty of Passau in 1552, which was in the main ratified by the Reichstag held at Augsburg in 1555 (the so-called Peace of Augsburg); but the arrangement was artificial and proved itself untenable as a permanent instrument of peace.
During the latter part of the sixteenth century two magnates of the empire, the Duke of Bavaria on the Catholic side and the Calvinist, Christian of Anhalt, on the Protestant, played the chief role, the Lutheran Markgrave of Saxony taking up a moderate position as mediator.

Of the Reichstag of Augsburg it should be said that it had ignored the Calvinist section of the Protestant party altogether, only recognizing the Lutheran.

In 1608 the Protestant Union, which embraced Lutherans and Calvinists alike, was founded under the leadership of Christian of Anhalt.