**PFAFF, CHRISTOPH MATTHÄUS.** - Lutheran theologian, b. in Stuttgart on 24 Dec. 1686, d. in Giessen on 19 Nov. 1760. As a ducal tutor and later as a professor at the University of Tübingen and then at Giessen, he promoted Pietism (v.) at the Württemberg court.
Due to the dogmatic indifference characteristic of Pietism, he advocated the union of Protestant Churches, provoking a reaction from intransigent Lutherans. A versatile but superficial writer, he owes a disputed reputation to the publication of four fragments attributed to Irenaeus, which were likely forged by him.
As a canonist, his name is linked to the first formulation of a theory regarding the structure of the Lutheran Church, which had wide application in the 19th century: the so-called "collegial system," according to which the Church would essentially be an association (*collegium aequale*), in which originally the full right to regulate the life of the association would belong to the entire body of the faithful; priests would be merely officials of the association, and the territorial lord would exercise ecclesiastical power as *summus episcopus* only by tacit or express consent of the association. This system paved the way in Germany for the separation between Church and State.