Calvinism was the religious tradition that gained legal recognition in the Holy Roman Empire through the Peace of Westphalia. The 1648 settlement placed Calvinists alongside Catholics and Lutherans as officially recognized confessions.
This mattered because the 1555 Peace of Augsburg had legally accommodated only Roman Catholicism and Lutheranism. Calvinism had spread widely in areas such as the Palatinate, Brandenburg, and parts of western Germany, but it remained outside Augsburg’s formal religious framework. That gap contributed to tensions before and during the Thirty Years’ War.
The Peace of Westphalia, negotiated mainly through treaties at Münster and Osnabrück, also established rules for determining religious and ecclesiastical rights based largely on the situation in 1624. It did not create complete religious freedom by modern standards, but it gave Calvinist rulers and communities a recognized legal position. A common mix-up is to assume that Anglicanism or Eastern Orthodoxy was added to the same settlement; neither received this status within the Empire.