A French 'Matthioli on the herbal of Dioscorides'; 1572.

Our knowledge of the ancient practice of medicine is scant, but we know it was established long before the 18th century BC when the Code of Hammurabi first set out laws governing the behaviour of doctors. In the few extant ancient sources, diagnosis and treatment are conjoined in the descriptions of cases or types of illness and there is no separate account of the medicines to be used. This changed in the 1st century AD when Dioscorides, a Greek practising medicine in Nero’s Rome, wrote a systematic account of the sources of medicaments whose Latin title, De materia medica, gave the topic its name. The herbal of Dioscorides remained the principal authority on the sources and preparation of medicines for one and a half millennia. Dioscorides was not the first to write about plants as sources of medicines; the treatise latinised as the Historia plantarum of Theophrastus, written about 300 BC, provided a rough framework for classification of the plants it described. Celsus’s De medicina then Pliny’s Naturalis historia, written in the 1st century AD and roughly contemporary with Dioscorides, contain information on sources and preparation of plant remedies. These authorities, interpreted and reinterpreted by many authors, of whom Avicenna in the 11th century was the most influential, together with Galenic writings, formed, with Dioscorides, the backbone of therapeutic practice until the Renaissance.