Andreas Libavius (ca. 1560-1616) is a well-known early modern physician and alchemist, who involved himself in various disputes. For example, in several of his writings he rejected the heterodox texts related to the Rosicrucian episode. This paper analyses Libavius's refutation of the Rosicrucian manifestos (1614-16), and aims to show that, in his response, Libavius presented himself not just as a member of the scholarly community, which is a well known facet of his life and career, but also as a Lutheran who aimed to protect his confession from attacks by heterodox sects.