Thucydides wrote a history of the epic struggle between Athens and Sparta. His work has proved to be—as he hoped—a "possession for all time," though perhaps not in quite the way he intended. Virtually every age, every occasion, every interpreter, has appropriated a different Thucydides and a different masterpiece. Both the author and the work remain enigmatic.

The reliable biographical details are few, and all derive from his own account. Thucydides son of Olorus was an Athenian, born around 460 BCE. In his analysis of the causes, symptoms, and consequences of the plague that devastated Athens a few years after the outbreak of hostilities with Sparta, Thucydides drew on his own experience of the illness. He was for a time prominent in Athenian public life. During the war, he attained the office of general, one of the very few elected positions in the...