History of the Peloponnesian War

The disease began, it is said, in Ethiopia beyond Egypt, and then descended into Egypt and Libya and spread over the greater part of the King's territory.

Then it suddenly fell upon the city of Athens, and attacked first the inhabitants of the Peiraeus, so that the people there even said that the Peloponnesians had put poison in their cisterns; for there were as yet no public fountains there. But afterwards it reached the upper city also, and from that time the mortality became much greater.

Now any one, whether physician or layman, may, each according to his personal opinion, speak about its probable origin and state the causes which, in his view, were sufficient to have produced so great a departure from normal conditions: but I shall describe its actual course, explaining the symptoms, from the study of which a person should be best able, having knowledge of it beforehand, to recognize it if it should ever break out again. For I had the disease myself and saw others sick of it.