If the war ends, the support of the holy order also ends, since such military organizations act independently from feudal interests. Time to declare war, capture Zeeland and be able to reform the religion at our leisure. A ruler of the same religion pays with Piety for the assistance of a holy order. Each new holding costs gold. If you want to try playing just as a vassal, however, France is a great place to start, with nothing much to do but play the diplomatic game.
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