PROTESTANT DIETS. - Assemblies of political-religious representatives from the states of Germany, the primates of the Kingdom of Hungary, and the envoys of Switzerland and the Scandinavian world. The principal Diets were those of Augsburg (1518, 1530, 1547, 1555, 1608), Worms (1521, 1530), Nuremberg (1523, 1524), Speyer (1526, 1529, 1544), Cologne (1530), Frankfurt am Main (1539), and Regensburg (1542–1621).
At the Diet of Worms, opened by Charles V on 28 January 1521, Luther appeared in person, while the Pope was represented by two legates—later cardinals—Marino Caracciolo (1459–1538), entrusted with political affairs, and Girolamo Aleandro (1480–1542), with ecclesiastical matters. At the Nuremberg Diet of 1522, prayers and processions were ordered, and a tax was imposed to ward off the Turkish threat. The papal legate present was Francesco Chieregati. At the first Diet of Speyer in the summer of 1526, the Protestant princes for the first time dared to proclaim their dissenting faith and demand the convocation of a general or national council to resolve the ecclesiastical question raised by the eruption of Luther’s reform. The looming Turkish invasion and the conflict between the Emperor and the Pope encouraged this bold stance of the Lutherans, after which every Protestant prince claimed and exercised the so-called right to reform religion, the *ius reformandi religionem*. From this arose the maxim, anti-Spiritual and anti-papal, that the political head of a territory is also its religious head: *Cuius regio, eius religio*. At the Augsburg Diet of 1530, held in the presence of Emperor Charles V, on 24 June the papal nuncio Lorenzo Campeggio—while from the tower of St. Stephen in Vienna the muezzin’s call to prayer could be heard—urged the German states not to separate from the Catholic Church and invited them to follow the example of other Catholic rulers. The next day, however, Dr. Bayer, vice-chancellor of Electoral Saxony, read out the Augsburg Confession, which was then signed by seven princes.
Fifteen Diets were held in Germany between 1848 and 1872 by representatives of German evangelical or "positive" Protestantism: Wittenberg (1849), Stuttgart (1850), Elberfeld (1851), Bremen (1852), Berlin (1853), Frankfurt (1854), Lübeck (1856), Stuttgart (1857), Hamburg (1858), Barmen (1860), Brandenburg (1862), Altenburg (1864), Kiel (1867), Stuttgart (1869), and Halle (1872). Their aims were to "heal the divorce" between the ideas and life of a large part of the nation and the doctrines of the Gospel, to bind the faithful in communion with one another as members of the one body of which Christ is the head, and to create a center of action to apply, where necessary, the remedies indicated by the word of God. The program, however, was frustrated by deep divisions among Lutherans, members of the so-called "positive union," and those of the center party (*Mittelpartei*). Thus, ecclesiastical Diets ceased to be held.