of the cities under the jurisdiction of an ecclesiastical prince if they had practiced Lutheranism for some time (Lutheranism was the only branch of Protestantism recognized under the Peace). The provision was not publicized as part of the treaty, and was kept secret for almost two decades. Problems The document itself had critical problems. While it gave legal basis for the practice of the Lutheran confession, it did not accept any of the Reformed traditions, such as Calvinism, nor did it recognize Anabaptism. Although the Peace of Augsburg was moderately successful in relieving tension in the empire and increasing tolerance, it left important things undone. Neither the Anabaptists nor the Calvinists were protected under the peace, so many Protestant groups living under the rule of a Lutheran prince still found themselves in danger of the charge of heresy. (Article 17: "However, all such as do not belong to the two above named religions shall not be included in the present peace but be totally excluded from it.") These minorities did not achieve any legal recognition until the Peace of Westphalia in 1648. The intolerance towards Calvinists caused them to take desperate measures that led to the Thirty Years' War. One of the more notable measures was the Third Defenestration of Prague (1618) in which two representatives of the fiercely Catholic King of Bohemia Archduke Ferdinand (Matthias was Emperor until 20 March 1619) were thrown out of a castle window in Prague. Aftermath The principle of ecclesiastical reservation was tested in the Cologne War (1583–1588), which grew out of the scenario envisioned by Ferdinand when he wrote the proviso: the reigning prince-archbishop, Hermann of Wied, converted to Protestantism; although he did not insist that the population convert, he placed Calvinism on a parity with Catholicism throughout the Electorate of Cologne. This in itself came forth as a two-fold legal problem: first, Calvinism was considered a heresy; second, the elector did not resign his see, which made him eligible, at least in theory, to cast a ballot for emperor. Finally, his marriage posed a very real potential to convert the electorate into a dynastic principality, shifting the balance of religious power in the empire. A side effect of the religious turmoil was Charles' decision to abdicate and divide Habsburg territory into two sections. His brother Ferdinand ruled the Austrian lands, and Charles' fervently Catholic son, Philip II, became administrator of Spain, the