(c. 460 BC - c. 375 BC)
Teaching for many years at one of the preeminent Greek medical schools on the island of Cos, Hippocrates argued that medicine should be based on observation, not magic; that illness was natural, not divinely sanctioned. Often referred to as the father of medicine, the body of work attributed to him helped establish more rational standards for practicing medicine. It is now widely believed that he wrote few, if any, of the roughly sixty texts belonging to the Hippocratic corpus. The oath that bears his name was appended to his corpus around five hundred years after his death.