The Athenian Thucydides has cast such a giant shadow over the domain of Klio that he cannot be ignored. Indeed so magisterial is his History of the Peloponnesian War that comparison with other historians is inevitable. It matters not whether the latter preceded him or followed in his wake; nor is their familiarity with the nature and methods of his work necessarily taken into account. In simple terms Thucydides has become a barometer by which to gauge the writing of history both past and present.

Born the son of Oloros of the deme Halimous in c. 454 BG, Thucydides lived during the most significant and exciting period in the history of ancient Athens, for among other things he was able to witness first hand the consolidation of the Athenian Empire, the emergence of radical democracy, the cultural effervescence of the “Golden Age of Pericles,” and the grueling civil war between Athens and Sparta. The total effect of these developments must have been overwhelming on any contemporary, especially one of Thucydides' intelligence and station. Given his education at the hands of sophists, he was probably all the more alert to the rapidly changing world around him and became determined to be a principal player in perpetuating the issue of events.