The Physician of Kos
Hippocrates was born on the island of Kos about 460 BCE, into a family that claimed descent from Asclepius and practised medicine as an inherited craft. Plato mentions him twice as a well-known teacher who took fees, which is the earliest and firmest evidence that he existed and was famous in his own lifetime. Aristotle calls him great. Beyond these glimpses, the biography is late and unreliable, embroidered by Soranus in the second century CE and by a batch of forged letters that turned him into a patriotic hero.
The body of writing attributed to him, the Hippocratic Corpus, was probably assembled at Alexandria and contains some sixty works composed between roughly 440 and 340 BCE, with some later additions. They differ in dialect, style, theory and quality: case notes, surgical manuals, treatises on air and water, gynaecological texts, aphorisms and philosophical polemics. Several contradict one another outright. No modern scholar can say with confidence which, if any, Hippocrates wrote himself, and the honest position is that the name marks a tradition rather than an author.
Nature Instead of Punishment
The Corpus is remembered for a single decisive move. The treatise on the sacred disease, meaning epilepsy, argues that the condition is no more divine than any other, that it has a natural cause in the brain, and that those who call it sacred are ritual healers disguising their ignorance behind piety. That argument does not depend on knowing the actual mechanism. It asserts that the body is part of nature, that its disorders follow regular causes, and that a physician's task is therefore to observe rather than to placate.
Observation is what these texts do best. The books of Epidemics record individual patients by name and neighbourhood, tracking fever, sleep, urine and sputum day by day, and they report deaths as often as recoveries. Prognosis, knowing how a case would run, mattered more than cure, because a physician's reputation rested on it. The underlying theory, a balance of four humours affected by climate, diet and season, was wrong, and it licensed centuries of bleeding and purging. The method of watching closely and writing it down outlasted the theory.
The Oath and Its Afterlife
The Hippocratic Oath is the most quoted medical text ever written and among the least representative. It swears by Apollo, Asclepius, Hygieia and Panacea, binds the physician to teach his master's children without fee, forbids giving a deadly drug or an abortive pessary, and reserves cutting for stone to practitioners who do that work. Its prohibitions do not match what other treatises in the Corpus describe as normal practice, and historians suspect it reflects one particular group rather than a profession-wide standard.
It was not central to medical life for most of history. Its rise to ceremonial prominence came largely after the Second World War, when the crimes of Nazi physicians made the profession urgently interested in written ethical commitment. The phrase most often attached to it, first do no harm, does not actually appear in it. What endures is not the specific list of rules but the idea underneath: that technical skill over a vulnerable body creates obligations, and that those obligations should be stated out loud.
