Like Katana said, the seeds of the Reformation were sown decades, centuries even before Luther. John Wycliffe, William Tyndale, Jan Hus etc etc.

Sadly I don't think the current TW diplomacy engine is anywhere near advanced enough to deal with something like the 30 year war. So many factions, so many factors influencing their actions. Ever tried explaining what the 30 Year War was about to someone who's never heard of it?

And then every other faction will just declare war on you anyway. *sigh*