The plague strikes Athens

'The bodies of dying men lay one upon another, and half-dead creatures reeled about in the streets. The catastrophe became so overwhelming that men cared nothing for any rule of religion or law.'

Thucydides 2.47 - 55.

Thucydides himself suffered from the plague and recovered, and was concerned with giving an accurate description of its symptoms and social consequences. Modern historians and researchers have not been able to identify the Athenian plague with any great certainty - some believe it to have been typhus, others think it could have been some sort of influenza.