“though no pestilence of such extent nor any scourge so destructive of human lives is on record any where. For neither were physicians able to cope with the disease, since they at first had to treat it without knowing its nature, the mortality among them being greatest because they were most exposed to it, nor did any other human art prevail. And the supplications made at sanctuaries, or appeals to oracles and the like were futile, and at last men desisted from them, overcome by the calamity” (Thucydides, Peloponnesian wars)