There had been a few small wars of this character before, such as those of Hesse against Bamberg and Wurzburg, and against Wuerttemberg, and against Brunswick.

But the conflicts had been successfully "localized." Now at last was to come a general battle, as a foretaste of the Thirty Years War of the next century.
It has sometimes been doubted whether the Schmalkaldic War was a religious conflict at all.

The emperor asserted that his sole object was to reduce rebellious subjects to obedience.

Several Protestant princes were his allies, and the territories he conquered were not, for the most part, forced to give up their faith.

Nevertheless, it is certain that the fundamental cause of the strain was the difference of creed.