The Peace of Westphalia was a series of peace treaties signed between May and October 1648 in Osnabrück and Münster. These treaties ended the Thirty Years' War (1618–1648) in the Holy Roman Empire, and the Eighty Years' War (1568–1648) between Spain and the Dutch Republic, with Spain formally recognizing the independence of the Dutch Republic. Other effects of the Peace of Westphalia were the formal recognition of the independence of the Swiss Confederacy, legal recognition of Calvinism within the Empire, and the beginnings of the modern system of state sovereignty.