'The greatest historian that ever lived'Such was Macaulay's verdict on Thucydides (c. 460-400 BC) and his history of the Peloponnesian War, the momentous struggle between Athens and Sparta as rival powers and political systems that lasted for twenty-seven years from 431 to 404 BC, involved virtually the whole of the Greek world, and ended in the fall of Athens. Thucydides himself was a participan...