The ancient Greeks invented democracy. They also invented political theory. This book seeks to show that these were not unrelated achievements. The development of political theory accompanied the growth of democracy at Athens in the fifth century BC. By analysing the writings of Protagoras the sophist, Thucydides the historian, and Democritus the cosmologist in the context of political developments and speculation about the universe, Dr Farrar reveals the existence of a distinctive approach to the characterisation of democratic order, and in doing so demonstrates the virtues of Thucydides' historical conception of politics. Thucydides' history is shown to be an argument for the political force of historical judgement.