Plutarch (; Greek: Πλούταρχος, Ploútarchos; Koinē Greek: [ˈplúːtarkʰos]; c. AD 46 – after AD 119) was a Greek Middle Platonist philosopher, historian, biographer, essayist, and priest at the Temple of Apollo in Delphi. He is known primarily for his Parallel Lives, a series of biographies of illustrious Greeks and Romans, and Moralia, a collection of essays and speeches. Upon becoming a Roman citizen, he was possibly named Lucius Mestrius Plutarchus (Λούκιος Μέστριος Πλούταρχος).
