for heart conditions. Unlike al-Razi, Avicenna explicitly disputed the theory of the transmutation of substances commonly believed by alchemists: Four works on alchemy attributed to Avicenna were translated into Latin as: was the most influential, having influenced later medieval chemists and alchemists such as Vincent of Beauvais. However, Anawati argues (following Ruska) that the de Anima is a fake by a Spanish author. Similarly the Declaratio is believed not to be actually by Avicenna. The third work (The Book of Minerals) is agreed to be Avicenna's writing, adapted from the Kitab al-Shifa (Book of the Remedy). Avicenna classified minerals into stones, fusible substances, sulfurs and salts, building on the ideas of Aristotle and Jabir. The epistola de Re recta is somewhat less sceptical of alchemy; Anawati argues that it is by Avicenna, but written earlier in his career when he had not yet firmly decided that transmutation was impossible. Poetry Almost half of Avicenna's works are versified. His poems appear in both Arabic and Persian. As an example, Edward Granville Browne claims that the following Persian verses are incorrectly attributed to Omar Khayyám, and were originally written by Ibn Sīnā: Legacy Classical Islamic civilization Robert Wisnovsky, a scholar of Avicenna attached to McGill University, says that "Avicenna was the central figure in the long history of the rational sciences in Islam, particularly in the fields of metaphysics, logic and medicine" but that his works didn't only have an influence in these "secular" fields of knowledge alone, as "these works, or portions of them, were read, taught, copied, commented upon, quoted, paraphrased and cited by thousands of post-Avicennian scholars—not only philosophers, logicians, physicians and specialists in the mathematical or exact sciences, but also by those who specialized in the disciplines of ʿilm al-kalām (rational theology, but understood to include natural philosophy, epistemology and philosophy of mind) and usūl al-fiqh (jurisprudence, but understood to include philosophy of law, dialectic, and philosophy of language)." Middle Ages and Renaissance As early as the 14th century when Dante Alighieri depicted him in Limbo alongside the virtuous non-Christian thinkers in his Divine Comedy such as Virgil, Averroes, Homer, Horace, Ovid, Lucan, Socrates, Plato and Saladin. Avicenna has been recognized by both East and West as one of the great figures in intellectual history. Johannes Kepler cites Avicenna's opinion when discussing the causes of planetary motions in Chapter 2 of Astronomia Nova. George Sarton, the author of