RESERVATUM ECCLESIASTICUM. — Name given to one of the most important clauses of the Peace of Augsburg (25 Sept. 1555) between the Protestants and Catholics of Germany.
After the second war, known as the Schmalkaldic War, which ended with the Truce of Passau (1552), the Lutherans, feeling themselves to be the stronger party, wanted to impose their conditions; Emperor Charles V delegated full powers to his brother, King Ferdinand, to negotiate the peace. The Diet of Augsburg opened on 5 Feb. 1555, and the negotiations were laborious; the Lutherans, who had previously gathered at Naumburg, had pledged themselves not to yield in the slightest on the Augsburg Confession (Lutheran). Ferdinand and the majority of the Catholic princes, unprepared to continue the war, were determined to make peace at any cost, despite the contrary opinion of the papal nuncios. The Lutheran princes therefore obtained what they wanted: the ius reformandi and the ius in sacra, that is, the right to impose the Augsburg Confession on their subjects (thus excluding Calvinism and every other Protestant denomination) and to be completely exempt from episcopal jurisdiction. In addition, all the “secularizations,” that is, the Church’s properties they had usurped up to the year 1552, passed definitively into their possession. Subsequent “secularizations” were declared invalid, but bishops and abbots who were direct members of the Empire could convert to Lutheranism, thereby losing all their rights over their bishoprics or abbeys of r. e.; this clause was given the name r. e.
The official text of the Treaty stated as follows: “Since the members of the Empire belonging to the two religions have been unable to reach an agreement on how to proceed with regard to ecclesiastics who will abjure the ancient religion, the King [Ferdinand] declares, by virtue of the full powers that the Emperor has conferred upon him, that any archbishop, bishop, prelate, or other member of the Catholic clergy willing to change his religion will thereby lose his office, dignity, and revenues, without prejudice to his honors. The Chapters and persons possessing, by tradition and right, the capacity to make ecclesiastical appointments shall be left entirely free to elect a person of the ancient religion in place of the resigning incumbent” (Lehmann, op. cit. in bibl., pp. 51–52).
Since the text of the Treaty asserted that “it had not been possible to reach an agreement” and that the r. e. was nothing more than a decree of the King, in the Emperor’s name, the Protestants agreed not to regard it as binding upon them. This led, as early as 1582, to the war known as the War of Cologne, concerning the city’s elector-archbishop, who wished to “secularize himself” while retaining his office. Violations of the r. e. by the Lutherans were so numerous that they became one of the most serious causes of the Thirty Years’ War (1618–48).