AP World History Practice Exam 2025 – The Comprehensive All-in-One Guide to Exam Success!

The Thirty Years' War, which lasted from 1618 to 1648, profoundly altered the political and religious landscape of Europe. A significant consequence of this conflict was the principle of cuius regio, eius religio, which translated means "whose realm, his religion." This principle established that rulers had the authority to determine the official religion of their own state, allowing for increased regional autonomy concerning religious practices.

The Peace of Westphalia, which ended the war, recognized the legitimacy of Protestantism in addition to Catholicism and solidified the right of autonomy for various states. This effectively allowed different territories within the Holy Roman Empire and beyond to choose their religious affiliation without interference from external powers, reinforcing the separation of church and state to a greater extent.

The other options do not accurately reflect the outcomes of the war: the Catholic Church did not regain control nor was Protestantism made the only recognized religion, and the idea of eliminating monarchies was contrary to the preservation and consolidation of state powers that took place during this period.