Peace of Augsburg, 1555
The Peace of Augsburg can be understood by one Latin phrase, cuius regio, eius religio, which translates as "whose region, his religion". The Peace of Augsburg, for the first time in the Holy Roman Empire, recognized and legitimized the idea of religious plurality. There was a limit to religious toleration however. Lutheranism was the only Protestant denomination considered legitimate to the exclusion of Calvinism and other more radical branches.
The Treaty was the result of the Schmalkaldic Wars, waged between Charles V and an alliance of northern German provinces. It would be the basis for religious plurality until the Peace of Westphalia in 1648 after the Thirty Years War.