This dissertation is about the persecution of the Waldenses, a group deemed heretical by the Catholic
Church, in German-speaking Europe in 1380–1410. The study has been structured around the literary
works of the most important contemporary inquisitor of heresy, the Celestine Petrus Zwicker (died
after 1404), and the circle around him. The larger cultural and political context is the Great Western
Schism (1378–1417).
The study proceeds from the exposition of polemical treatises and inquisitor’s manuals to the dissemination,
propagation and popularisation of these texts, as well as their role in the religious controversies
of the schism. First, two polemical treatises written against the Waldenses are analysed. The
author of the earlier of these, known as the Refutatio errorum, has not previously been identifi ed.
Extensive evidence is provided to confi rm Petrus Zwicker as the author of the work. Moreover, the
Refutatio is defi ned to be a draft-like compilation that precedes the better-known treatise Cum dormirent
homines, which became extremely popular in the fi fteenth century.
This dissertation offers the fi rst general view of the inquisitorial compilations transmitted under
Zwicker’s authorship, their characteristics, the texts included in them and the relationship of these
compilations to the earlier inquisitors’ manuals. The compilations containing Zwicker’s texts provide
detailed descriptions of the Waldenses and guidelines for their interrogation, but they lack the legal
consultations that were integral to the earlier manuals. Therefore, almost all the surviving manuscripts
should be regarded as general guidelines intended for the clergy rather than professional inquisitor’s
manuals.
In the period under study some antiheretical texts and ideas contained within them were effectively
disseminated to a readership wider than the clergy. The treatises written by Zwicker’s circle were
transmitted in vernacular translations and in sermon collections. Before this dissertation, these
sources have not been extensively analysed in studies on Zwicker’s antiheretical texts. The arguments
against Waldensian heresy did not touch only this heretical group, but commented on the larger religious
and cultural currents that questioned the authority of the Church and the clergy in the times of
the Great Schism. The treatises written by Zwicker were part of the greater late medieval debate about
the interpretation of the Bible and the unity of the Church.
This whole phenomenon is termed the ‘retheologisation of heresy’, meaning the revival of the doctrinal
and debating polemical style at the end of the fourteenth century, a shift in the interrogations
towards inquiry into laypersons’ personal beliefs, and the spillover of the antiheretical polemics into
pastoral theological genres.