Final answer:
The 30 Years War began as a struggle between Catholicism and Calvinism, and later expanded to involve political and territorial disputes. It had a significant impact on Europe.
Step-by-step explanation:
The 30 Years War began as a struggle between Catholicism and Calvinism. It started as a religious conflict in Central Europe between the Holy Roman Empire, which was predominantly Catholic, and various Protestant states, including Calvinists and Lutherans. The war later expanded to involve other political and territorial disputes, with France and Sweden siding with the Protestant states against the Catholic Habsburgs. It caused immense devastation and reshaped the balance of power in Europe.
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