History of the Peloponnesian War covers the events of the first twenty years of the late fifth-century BC war between two alliances led by Sparta and Athens. Thucydides , an Athenian general in the war and thus a first-hand witness to many of its events, begins with his views on what led to the war, with the remainder of the book devoted to the events of the war itself. His history covers the first twenty of the twenty-seven years of the conflict, cutting off almost immediately after the devastating Athenian defeat at Syracuse.

Perhaps the most famous aspect of his history are the numerous speeches it contains. Thucydides acknowledges that they were often reconstructed from what he thought the occasion demanded, while trying to stick as closely as possible to what was actually said. Many of the speeches are the back and forth between two parties as they argue their respective cases before an administrative body, and they offer a fascinating view of different perspectives of the same set of events.

Although Thucydides’ history came soon after Herodotus’ , it differs in significant ways. Thucydides makes no mention of the role of gods in any of the events he reports, and his history is chronological, with a sentence concluding the end of each campaign year. He also states that he sifted through differing versions of events to discern what actually happened, in an attempt to be unbiased in what he presented. He also focused solely on the events of the war, rather than also delve into the surrounding culture. For these reasons, he has been called “the father of scientific history.”