Jean de Roquetaillade, also known as John of Rupescissa (14th c.) was a French monk and alchemist of dubious reputation. John de Rupecissa was a Franciscan who gained fame in about the mid-14th century, especially for his alleged prophecies. Pope Innocent VI found his prophecies so offensive that he had him arrested and imprisoned in the Vatican dungeons. According to lore, de Rupecissa died there.
His alchemical treatises are De Confectione Lapidis, his major work, and Book of Light, Five Essences, and Heaven of Philosophers. De Rupecissa was regarded as a pretender by other alchemists. bernard of Trèves, however, took his work seriously.