During the Peloponnesian War a plague broke out in Athens. We aren’t sure what kind of plague it was but one theory is that it was a bubonic plague. it killed one quarter of all residents including the great Athenian leader Pericles. The historian who gives us our most complete account of the War was Thucydides and he also came down with the plague but he survived. The Spartans left the area around Athens for awhile because of their fear of the plague.

(The Great Courses – The Long Shadow of the Ancient Greek World)