Polybus, Not the Son-in-Law of Hippocrates

Abstract Hippocrates is traditionally believed to have had a son-in-law and pupil named Polybus, who, thanks to Aristotle’s direct attribution, is also often regarded as the author of the surviving ‘Hippocratic’ treatise On the Nature of the Human Being ( Nat. Hom .), the source of the canonical theory of the four humours. This article accepts that Polybus was indeed the author of On the Nature of the Human Being , but aims to show that his status as Hippocrates’ son-in-law is a Hellenistic invention, inspired by the conflicting attribution of the treatise to Hippocrates once it had become part of the Hippocratic Corpus. This also allows a re-dating of On the Nature of the Human Being to the mid fifth century, so that both Polybus and his four-humour theory likely predate Hippocrates’ period of activity.