Often regarded as the father of realism in international relations, Thucydides was a historian and an original political thinker, best known for his description and analysis of the political events that occurred during the Peloponnesian War, which broke out in 431 B.C.E. between Athens and Sparta. Thucydides, an Athenian citizen, was a contemporary of these events. He was born around 460 B.C.E., and in 424 attained the rank of general. Because he was unable to defend the city of Amphipolis from the Spartans’ attack, charges were brought against him. He was forced into a twenty-year exile, during which he spent most of the time at his home in Thrace, but he also visited the Peloponnesus and traveled to Sicily. He returned to Athens after the war ended, but did not live long enough to finish his History of the Peloponnesian War . The account breaks off in 411, seven years before the end of the war.