Pedanius Dioscorides (Greek: Πεδάνιος Διοσκουρίδης, Pedánios Dioskourídēs; c. 40–90 AD) was a Greek physician, pharmacologist, botanist, and author of De materia medica (Περὶ ὕλης ἰατρικῆς, On Medical Material) —a 5-volume Greek encyclopedia about herbal medicine and related medicinal substances (a pharmacopeia), that was widely read for more than 1,500 years. He was employed as a physician in the Roman army.