The major religious conflict that shaped history during the Thirty Years' War in Europe was the struggle between Catholicism and Protestantism. Spanning from 1618 to 1648, this devastating war involved multiple European powers. Initially ignited by religious tensions in the Holy Roman Empire, it evolved into a broader conflict encompassing political and territorial disputes. The war’s aftermath significantly altered the political landscape of Europe, leading to the Treaty of Westphalia, which established principles of state sovereignty and religious tolerance, marking the end of religious wars in Europe.