Collected Alchemical writings of Philippus Aureolus Theophrastus Bombastus von Hohenheim including: Coelum philosophorum The Book Concerning The Tincture Of The Philosophers The Treasure of Treasures for Alchemists The Aurora of the Philosophers Paracelsus (born Philippus Aureolus Theophrastus Bombastus von Hohenheim, 11 November or 17 December 1493 - 24 September 1541) was a German-Swiss Renaissance physician, botanist, alchemist, astrologer, and general occultist. He founded the discipline of toxicology. He is also known as a revolutionary for insisting upon using observations of nature, rather than looking to ancient texts, in open and radical defiance of medical practice of his day. He is also credited for giving zinc its name, calling it zincum, and for the terms "gas," "chemistry," and "alcohol." Modern psychology often also credits him for being the first to note that some diseases are rooted in psychological illness. His personality was stubborn and independent. He grew progressively more frustrated and bitter as he became more embattled as a reformer. "Paracelsus", meaning "equal to or greater than Celsus", refers to the Roman encyclopedist Aulus Cornelius Celsus from the 1st century, known for his tract on medicine.