In a recent re-assessment of the medical aspects of the Plague of Athens which is, to date, the most scholarly and comprehensive, Poole and Holladay have emphasized the tendency of many infectious diseases markedly to decline in virulence over decades and centuries and, sometimes, significantly to change their clinical manifestations. In the light of modern medicine they consider four possibilities: (i) The Plague was a disease (or combination of diseases) which still exists today. This they regard as improbable, (ii) It still exists in some remote place or places unknown to medical science. This is discussed and dismissed, (iii) It became extinct, (iv) It was caused by an agent which nowadays causes a significantly different clinical syndrome. They conclude as follows: ‘The truth, we suggest, almost certainly lies in possibility (iii) or (iv). But we can see no way of choosing between them. On either view the question: “What was the Athenian Plague?” is in principle unanswerable if the questioner is wanting to attach to the Plagsie the name of some modern disease or diseases’.