Thucydides claimed that his account of the devastating war between the Athenians and the Spartans was a possession for all time. An Athenian general, he was exiled for a military failure and drew for his writing on his personal experience and information from an extensive network of contacts on both sides to the epic conflict. His work is shaped by his judgements about the exercise of power in a democracy which ruled an empire and by his analysis of the impact of war on the social fabric. Thucydides's technique draws on the culture of his time, including sophist rhetoric, the drama of Greek tragedy and the diagnostic methods of the Hippocratic medical writers. The issues Thucydides addressed are as germane today as they were in the 5th-century BC.