Plutarch of Chaeroneia, Platonist philosopher, biographer and antiquarian, was born to a family of local aristocrats in the small town of Chaeroneia in Boeotia in about 45 ce. He studied philosophy in Athens under Ammonius, a Platonist philosopher from Egypt, who had settled in Athens and had become prominent in Athenian society. He travelled widely around the Mediterranean, visiting Asia Minor and Egypt, and made a number of visits to Rome, beginning in the 90s, where he gave lectures and became acquainted with many prominent Romans, including Q. Sosius Senecio and L. Mestrius Florus (whose name he adopted on becoming a Roman citizen). In later years he retired to Chaeroneia, where he formed a philosophical circle and composed most of his works. He was also closely connected with Delphi, of whose priesthood he was a member. In his old age, he was bestowed by the Emperor Hadrian with the honorary position of Procurator of Achaea. He died about 120 ce.

Plutarch left a vast body of work, much of which has survived (although his more technical philosophical works – of which a list has been preserved – have been lost). His most famous work is the Parallel Lives, in which he presents for comparison a series of lives of distinguished Greeks and Romans, but we also have a large collection of Moral Essays, including some important dialogues, such as On Isis and Osiris (hereafter De Is.), On the E at Delphi (hereafter De E), On the Oracles at Delphi, On Delays in the Divine Punishment, On the Daemon of Socrates (hereafter De genio), and On the Face on the Moon (hereafter De facie).