Thucydides, the greatest of ancient historians, was the first to make accurate reporting his primary duty and the first to establish wad and politics as history's foremost subjects. But the writing of history was not defined as a literary activity until Aristotle and Thucydides clearly does not conform to Aristotle's restricted definition. To understand how Thucydides perceived himself and his enterprise Simon Hornblower places him in intellectual context against the background of fifth-century Greek philosophy, tragedy, rhetoric, medicine and previous historiography.