to Luther. Before ten years had elapsed the greater part of Northern
Germany had fallen from the Catholic Church, and even in Southern
Germany Protestantism had made serious inroads. Several of the more
important cities such as Wittenberg, Strassburg, Nurnberg, Magdeburg,
Frankfurt-on-Main, Hamburg, and Erfurt became leading centres for the
spread of the new teaching, while many of the German universities, for
example, Erfurt, Basle, Frankfurt, Rostock, and Marburg supported
strongly the efforts of Luther.

The Catholic princes, alarmed by the rapid spread of the new doctrines
and by the extravagant demands of the Protestants, met together to
form the Holy League (1538) as a defence against the Schmalkaldic
confederation. Feeling was running so high at the time that the long
expected war might have broken out immediately, had not the dread of a
Turkish invasion exercised a restraining influence on both parties. In
1539 negotiations were opened up for a temporary armistice, and
another fruitless attempt was made to arrive at peace by means of a
religious conference. Before any result had been attained the Emperor
summoned a Diet to meet at Ratisbon (April 1541). Three theologians
were appointed from both sides to discuss the questions at issue.
Though some of the Catholic representatives showed clearly enough that
their desire for union was much greater than their knowledge of
Catholic principles, an understanding was arrived at only in regard to
a few points of difference. By the Recess of the Diet (known as the
/Ratisbon Interim/) it was ordered that both parties should observe
the articles of faith on which they had agreed until a General Council
should meet, that in the interval the terms of the Peace of Nurnberg
should be carried out strictly, that the religious houses that had
escaped destruction hitherto should remain undisturbed, and that the
disciplinary decrees promulgated by the cardinal legate (Contarini)