Portrait of Platearius with urinoscopy flask. Matthaeus Platearius was a physician from the medical school at Salerno, and is thought to have produced a twelfth-century Latin manuscript on medicinal herbs titled "Circa Instans" aka "Liber de Simplici Medicina" ("The Book of Simple Medicines"). It was an alphabetic listing and textbook of simples that was based on Dioscorides "Vulgaris", which described the appearance, preparation, and uses of various drugs. It was widely acclaimed, and was one of the first herbals produced by the newly developed printing process in 1488. Matthaeus and his brother Johannes were the sons of a female physician from the Salerno school and married to Johannes Platearius I. She is surmised to be Trotula of Salerno, who wrote some important treatises on gynecology including Diseases of Women.