Original: The Peace of Westphalia treaties involved the Holy Roman Emperor , Ferdinand III of the House of Habsburg , the Kingdoms of Spain , France , Sweden , the Dutch Republic , the Princes of the Holy Roman Empire , and sovereigns of the Free imperial cities and can be denoted by two major events .
Simplified: All parties would now recognize the Peace of Augsburg of 1555 , by which each prince would have the right to determine the religion of his own state , the options being Catholicism , Lutheranism , and now Calvinism .