This paper
discusses the causes of the Peloponnesian
War, and the nature in which it took place. It discusses Thucydides'
view that the underlying reason for the
war was Spartan fear of Athens, as well as the more immediate factors. Finally, it examines how the structure of the Athenian and Spartan states gave the war its longevity, which only ended when an external power, Persia, became involved.