The main reasons for the Thirty Years War?

The main reasons for the Thirty Years War: religious differences between different denominations; struggle for dominance in Europe.

The Thirty Years’ War itself was a religious conflict from the very beginning, but then it turned into a pan-European conflict, where the struggle was against the hegemony of the Habsburgs. Ultimately, the position of the Habsburgs was weakened. At the same time, domination was able to pass to France, and Sweden was able to become a world state. Spain, in turn, fell into decay.