[1][2] The first to propose making the Corpus Evangelicorum (i.e., the Protestant states collectively) an integral part of the empire's constitution was King Gustavus Adolphus of Sweden.
Shortly before his death in 1632, he proposed as a settlement of the Thirty Years' War the establishment of a corpus politicum (political body) composed only of Protestant princes for civil administration and a corpus bellicum (body of war) for matters of defence.
Gustavus' intention was mainly to limit the authority of the imperial Habsburg dynasty to their own lands and to strengthen Swedish domination of the Protestant part of the Empire.
[3][4] The Peace of Westphalia (which ended the Thirty Years' War) enshrined the corpora in the imperial constitution and introduced the itio in partes procedure for religious matters.
[1][5] The separation of the Catholic and Protestant states at the Westphalian peace conference (1645–48) was itself the model for the itio in partes.
Each body would formulate its position separately before coming together to negotiate an "amicable agreement" (amicabilis compositio).
In practice, actual control of the directorate was transferred to a cadet branch of the Saxon house, the Dukes of Weissenfels.
[10] In response, Saxony's chief rival for the directorate, Brandenburg, assumed the role of vice-director.
[11] Under the influence of Brandenburg and Hanover, the Corpus drew up a list of 432 gravamina (grievances), published at Regensburg in 1719.
This made it to Brandenburg's advantage to claim that every issue was a religious one and to try to force an itio in partes.
The Catholics insisted that an itio could only be demanded if both sides agree that the question was religious in nature.