Structure of the Imperial Diet of the Holy Roman Empire

Timeline

1. 1356Metz and Nuremberg · Holy Roman EmpireCharles IV issued the Golden Bull, formally confirming the seven electors' right to elect the emperor and their privileges, fixing the core membership structure of the Imperial Diet. The Bull hereditized electoral rights and granted high autonomy, laying the institutional prototype of the Diet's tripartite structure.
2. 1495–1555Worms · Holy Roman EmpireThe 1495 Diet of Worms passed the Eternal Peace, established the Imperial Supreme Court, and the Diet's three-college system gradually took shape. During the Reformation the Diet became a stage for Protestant-Catholic princely rivalry, and the 1555 Peace of Augsburg temporarily stabilized the religious division with the principle 'cuius regio, eius religio'.
3. 1618–1648Holy Roman Empire · Holy Roman EmpireDuring the Thirty Years' War the Imperial Diet was virtually defunct; Emperor Ferdinand II bypassed it to implement Catholic restoration policies, issuing the Edict of Restitution in 1629 to forcibly reclaim Protestant territories. 1621-1630 was one of the war's fiercest phases, with armed conflict between the Protestant and Catholic leagues nearly halting proceedings and the empire's constitutional framework on the brink of collapse.
4. 1648–1663Osnabrück and Münster · Holy Roman EmpireThe Peace of Westphalia wrote the principle of religious equality into imperial law and established the 'itio in partes' voting-by-confession mechanism, preventing a Catholic majority from forcing resolutions. The Diet's procedural rules were substantially revised, and the rights of the three confessions (Catholic, Lutheran, Reformed) formally guaranteed.
5. 1663–1806Regensburg · Holy Roman EmpireFrom 1663 the Imperial Diet resided permanently in Regensburg, becoming a semi-diplomatic body of delegations from the various states, mocked by critics as an 'eternal talking shop' for its sluggishness. In 1806 Napoleon forced Francis II to dissolve the Holy Roman Empire, and the Diet ended with it, closing over four centuries of imperial constitutional history.