This paper aims to explore some possible sources of Francis Bacon’s peculiar way of relating idolatry, natural history and the medicine of the mind. In the first section, I argue that Bacon’s strategy of internalizing idolatry is not unlike that of some of the leading Calvinist reformers. If in using natural history as a therapy against the idolatrous mind Bacon departed from Calvin, this departure, I claim, was not unlike the road taken earlier by another important reformer, Pierre Viret (1511–1571). In elaborating a form of spiritual medicine, Pierre Viret gave prominence to the empirical and the “anatomical” study of nature. In the second part of my paper, I focus on a particular kind of Calvinist writings against idolatry: the French “Neo-Stoic” Calvinism of the late sixteenth century. I discuss the ways in which the Neo-Stoic Huguenots (and their English followers) used an empirical, anti-dogmatic and “literal” study of the Book of Nature—under the name of “natural history”—as a weapon in the war against the idols of the mind. In particular, I compare Bacon’s form of natural historical “therapy” with the one advocated by Pierre de la Primaudaye (1546–1619).