Polybus, Not the Son-in-law of Hippocrates

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 B.C., so that both Polybus and his four-humour theory likely pre-date Hippocrates’ period of activity.