Thu·cyd·i·des (thōō-sĭd'ĭ-dēz') Greek historian. Considered the greatest historian of antiquity, he wrote a critical history of the Peloponnesian War that contains the funeral oration of Pericles.
An ancient Greek historian and general. Thucydides' history of the Peloponnesian War, in which he fought, is famous for its careful reporting of events and its sharp analysis of causes and effects.