Oh shit the War of the Protestant League (basically the Thirty Years War) broke out. It's technically of a fight over whether the Emperor is a Protestant or a Catholic, but it's mostly just a way for everyone to get together and have a big war. That it's not really about religion is easily seen by how many Catholic countries are fighting each other.
In the following screenshot you can see who is on. All the red countries are on one side, all the green are on the other.
@BD being blue here means they're allied to RedSky (who I have selected), but have
not chosen a side. Also that means
@V.O. and
@adexkola are not in it (because they were in a war already), but
@Andycoleno9 is in it (I think because he was allied to the leader of the Protestant League.
Oh yeah, and the leader of the Protestand League is the tiny country of Opole, which seems like it's a bad idea.