8. The assistance rendered him by Melanchthon caused a
fierce attack on the theologian by his fellow-Lutherans. In enforcing
the Interim Maurice found his own profit, for when Magdeburg won the
nickname of "our Lord God's pulpit" by refusing to accept it, Maurice
was entrusted with the execution of the imperial ban, and captured the
city on November 9, 1551.

Germany now fell into a confused condition, every state for itself.
The emperor found his own {130} difficulties in trying to make his son
Philip successor to his Brother Ferdinand. His two former Protestant
allies, Maurice and John von Kuestrin, made an alliance with France and
with other North German princes and forced the emperor to conclude the
Convention of Passau. [Sidenote: 1552] This guaranteed afresh the
religious freedom of the Lutherans until the next Diet and forced the
liberation of John Frederic and Philip of Hesse. Charles did not
loyally accept the conditions of this agreement, but induced Albert,
Margrave of Brandenburg-Culmbach, to attack the confederate princes in
the rear. After Albert had laid waste a portion of North Germany he
was defeated by Maurice at the battle of Sievershausen. [Sidenote:
July 9, 1553] Mortally wounded, the brilliant but utterly unscrupulous
victor died, at the age of thirty-two, soon after the battle. As the
conflict had by this time resolved itself into a duel between him and
Charles, the emperor was now at last able to put through, at the Diet
of Augsburg, a settlement of the religious question.

[Sidenote: Religious Peace of Augsburg, September 25, 1555]

The principles of the Religious Peace were as follows:

(1) A truce between states recognizing the Augsburg Confession and
Catholic states until union was possible. All other confessions were
to be barred--a provision aimed chiefly at Calvinists.

(2) The princes and governments of the Free Cities were to be allowed
to choose between the Roman and the Lutheran faith, but their subjects
must either conform to this faith--on the maxim famous as _cujus regio
ejus religio_--or emigrate. In Imperial Free Cities, however, it was
specially provided that Catholic minorities be tolerated.

(3) The "ecclesiastical reservation," or principle that when a Catholic
spiritual prince became Protestant he should be deposed and a successor
appointed {131} so that his territory might remain under the church.
In respect to this Ferdinand privately promised to secure tol