On October 24, 1648, the Holy Roman Empire, Sweden, Spain, France, several German princi-palities, etc. signed what became known as the Treaty of Westphalia, or the Peace of Westphalia, ending thirty years of war among European sovereigns, ostensibly about whether the Roman Catholic Church or the several reformed churches should be practiced or forbidden, but actually about the prerogatives of political sovereignty. Though the sovereigns continued to disagree about church matters, they agreed completely that their rule would be absolute in the places they controlled.