John of Roquetaillade (DE RUPESCISSA), Franciscan alchemist, date of birth unknown; d. probably at Avignon, 1362. After pursuing the study of philosophy for five years at Toulouse, he entered the Franciscan monastery at Orleans, where he continued his studies for five years longer. His experiments in distillation led to the discovery of what he termed aqua vitae, or usually quinta essentia, and commended as a panacea for all disease. His work as an alchemist forms the subject-matter of “De consideratione quintae essentiae” (Basle, 1561) and “De extractione quintae essentiae”; likewise “Libellus de conficiendo vero lapide philosophico ad sublevandam inopiam papae et cleri in tempore tribulationis” (Strasburg, 1659). His false prophecies and violent denunciation of ecclesiastical abuses brought him into disfavor with his superiors, resulting in his imprisonment by Clement VI (1345) and Innocent VI (1356). While there he wrote in 1349 his “Visions seu revelations”, and in 1356 “Vade Mecum in tribulatione “and “Ostensor” (in Brown, “Fascicula rerum expetendarum et fugiendarum”, IIT, London, 1640). His other works include commentaries on the Sentences and on the “Oraculum Cyrilli”, “Fragmenta revelationum”, “Apologus propheticus”, “De famulatu philosophiae ad theologiam”.
F. M. RUDGE