Alchemy,Prophecy, and Politics in Eighteenth-Century Iberia: Anselmo Castelo Branco's Critique of Benito Feijoo

The Benedictine monk Benito Jerónimo Feijoo (1676–1764) is now considered one of the major figures of the Spanish and Iberian Enlightenment. However his work, both in Spain and in Portugal, was far from being universally acclaimed. His critical approach to the subject of alchemy in his essay “Piedra Filosofal,” published in the third volume of his magisterial Teatro Crítico Universal (1726–1739), sparked an unexpected response from the Portuguese alchemist Anselmo Castelo Branco, who sought to refute Feijoo's claims in his own work, the Ennoea. This paper presents an outline of this exchange and its position within Iberian Enlightenment circles. It further argues that Castelo Branco's defence of alchemy was informed by his political and prophetic views, in particular his adherence to the Portuguese messianic doctrine of Sebastianism.