Plutarch's best-known work is the Parallel Lives, a series of biographies of famous Greeks and Romans, arranged in pairs to illuminate their common moral virtues and vices. The surviving Lives contain 23 pairs, each with one Greek Life and one Roman Life, as well as four unpaired single Lives. This is Vol I of the work. Plutarch subsequently named, on becoming a Roman citizen, Lucius Mestrius Plutarchus ( circa 46 - 120 AD), was a Greek historian, biographer, and essayist, known primarily for his Parallel Lives and Moralia. He was born to a prominent family in Chaeronea, Boeotia, a town about twenty miles east of Delphi.