Jabir ibn Hayyan (c. 721–c. 815) Jabir ibn Hayyan was the first of many well-known alchemists from the Islamic world. Born in Iran to parents of Arab descent, his life took place against a backdrop of political turmoil. His father was executed for conspiring to overthrow the Umayyad caliphate. Jabir often found himself on the run as his patrons rose to and fell from power. Far from an ivory-tower academic, Jabir came to alchemy through his practical work as an apothecary. He was influenced by the Neo-Platonists and other ancient Greek writers whose works were then being translated into Arabic. He added to classical alchemical thought and practice in several ways. In alchemical practice, he added plant and animal substances to the metals and earths that dominated ancient classical alchemy. This could possibly reflect his background in preparing medicines, and no doubt reflects his concern with the practical aspects of material transformations. On the theoretical side, he built on the ideas of Aristotle, the Greek philosopher, who had formalized the idea that all matter was made of four elements: earth, air, water, and fire. To these, Jabir added the concept of "natures," which he listed as hotness, coldness, dryness, and wetness. Natures paired to make elements, in Jabir’s system. For example, hotness and dryness combined to make fire. Jabir professed that metals were formed from mercury and sulfur in varying combinations, and that achieving the right combination would produce gold. In this regard he was the founder of the mercurialist school of alchemy, a long tradition whose adherents would one day include Robert Boyle and Isaac Newton.