–between Holy Roman Emperor Charles V and the Schmalkaldic League, an alliance of Lutheran princes.
Augsburg (now in present-day Bavaria, Germany): Since the proclamation of a reformed church by Martin Luther, the problems of the co-existence of Catholics and Lutherans on the same territory had bedeviled the Holy Roman Empire. At Augsburg the Holy Roman Empire represented by the Ferdinand I, the brother of Holy Roman Emperor Charles V, confronted an alliance of Lutheran princes, who came under the rubric of the Schmalkaldic League. An agreement was reached.
The Peace (treaty) established the principle of Cuius region, eius religio, meaning for each region, its religion. Meaning, the insurgent Lutheran princes effectively prevailed.
The Peace of Augsburg allowed each of the empire’s princes to select one of the two religions as the official state religion for his principality. Subjects, citizens or residents who did not wish to conform their own practices to that of the prince were urged to migrate to a religiously consonant principality.