Among the manuscripts formerly held in the library of the Görlitz Gymnasium—known as the Milich Library and now housed at the University Library in Wrocław—there is a codex bearing the shelfmark Mil. II 52. In addition to sermons, quaestiones disputatae, and theological treatises, it contains a short anonymous text directed against the Waldensians, which, as far as current research suggests, survives only in this single copy. Although the work may have been composed somewhat earlier, the manuscript as a whole was copied in the 1460s or 1470s. This suggests that, at that time, someone still perceived the Waldensians as a tangible threat. The treatise draws in part on De inquisitione haereticorum, a work attributed to Pseudo-David of Augsburg, but also includes original passages. Our article contains the first edition of this text, accompanied by an introduction and a concise description of the manuscript.