(2.48) The disease is said to have begun south of Egypt in Aethiopia; thence it descended into Egypt and Libya, and after spreading over the greater part of the Persian empire, suddenly fell upon Athens. It first attacked the inhabitants of the Piraeus, and it was supposed that the Peloponnesians had poisoned the cisterns, no conduits having as yet been made there. It afterwards reached the upper city, and then the mortality became far greater. As to its probable origin or the causes which might or could have produced such a disturbance of nature, every man, whether a physician or not, will give his own opinion. But I shall describe its actual course, and the symptoms by which any one who knows them beforehand may recognise the disorder should it ever reappear. For I was myself attacked, and witnessed the sufferings of others.