Dioscorides (2) (Pedanius Dioscorides) (1st cent. ce), of Cilician Anazarbus, wrote an extensive, five-book work on the drugs employed in medicine. Dioscorides studied under Areius of Tarsus and travelled extensively collecting information about the medicinal uses of herbs, minerals, and animal products. His travels took him to the Greek mainland, Crete, Egypt, and Petra, but he mentions plants from much further afield. In the Preface he describes his travels as leading to a ‘soldier-like life’, a statement that led later writers to conclude, probably falsely, that he was once a physician in the Roman army.Dioscorides' Περὶ ὕλης ἰατρικῆς (Materia medica, ‘Materials of Medicine’), bks. 1–5, lists approximately 700 plants and slightly more than 1,000 drugs, and includes a letter to Areius that serves as an introduction. His method was to observe plants in their native habitats and to research previous authorities on these subjects. Finally he related the written and oral data to his clinical observations on the effects the drugs had on and in the body. He also provided data on preparations, adulterations, and veterinary and household usages. Dioscorides boasted that his method of organization was superior to that of previous works. His scheme was first to organize by categories, such as whole animals, animal parts and products, minerals, and plants—the last subdivided into roots, pot-herbs, fruits, trees, and shrubs. Within each category he arranged drugs according to their physiological reaction on the body. This arrangement by drug affinities was not explained and, as a consequence, many later copyists of his text rearranged his system according to the alphabet thereby obscuring the genius of his contributions. Dioscorides' information aims at medical precision, and his account is relatively free of supernatural elements, reflecting keen, critical observation of how drugs react. His medical judgements were well regarded until the 16th cent. Manuscripts of the Materia medica in Greek, Latin, and Arabic are often beautifully illuminated and indicate that Dioscorides' original text was accompanied by illustrations.