Ferdinand II, was the succesor from Ferdinand I and what he accepted was the Protestant and the Catholic in the Holy Roman Empire, but Ferdinand II just accepted the Catholic ways and many people disagreed.

The Thirty Year War: It began right after the defenstration of Prague and it had a war between the protestants and the catholics so Europe was divided in to two so people were supporting on different belief.

Jan 1, 1618

So the both sides that were supported are the Catholics and Protestants. The ones who were supporting the Catholics: Spain, and France. The ones supporting the Protestants: Denmark, Sweden, and England. So the Protestants were in the advantage.

Apr 24, 1618

Then in the same year visiting Prague the people introduced Ferdinand II by defenstrating him throwing him out of the window and that is what created the 30 years war

May 23, 1618