Rheticus was an Austrian mystic and mathematician who studied under, and was the most outspoken advocate of, Copernicus, and who arranged for the posthumous publication of Copernicus's De revolutionibus orbium coelestium (1543). Rheticus, also known by his non-Latinized name Georg Joachim von Lauchen, was the son of an alchemist, astrologer, and magician beheaded for sorcery. He studied mathematics at Zürich, where he met Paracelsus, became professor of mathematics and astronomy at Wittenberg from 1536, and, in 1540, published Narratio prima de libris revolutionum Copernici, the first written account of Copernican theory. Having convinced Copernicus shortly before his death to allow publication of De Revolutionibus, Rheticus unfortunately left the manuscript in the hands of a Lutheran minister, Andreas Osiander, who didn't believe in the Copernican system as a physical model. Consequently, Osiander added an unauthorized preface stating that the contents was merely a device to simplify calculations.