Seneca, Lucius Annaeus , a Roman philosopher and dramatist. Seneca's philosophical works are concerned with the wise conduct of life in the spirit of Stoicism. As a teacher of ethics and morals he was noted for his practical advice rather than abstract speculation. The Moral Letters, for example, are informal instructions for his friend Lucilius. The Naturales Quaestiones ("Physical Problems"), a work in which he discussed morals and natural phenomena, became a popular science textbook in the Middle Ages.

Seneca is believed to have written nine tragedies; they are the only surviving dramas from the Roman Empire. They were based on Greek models and apparently were designed for dramatic reading rather than staging. They are characterized by gloom, horror, and bombastic style. Renaissance and Elizabethan dramatists regarded them as model tragedies and drew heavily from them.

Seneca was born in Corduba (now Córdoba), Spain, into a wealthy family. He studied in Rome. Seneca was the tutor of the young Nero and served as his adviser after Nero became emperor in 54 A.D. In 65 A.D. Seneca was accused of participation in a conspiracy to depose Nero and committed suicide at the emperor's demand.

Other philosophical treatises of Seneca are On Clemency, On Anger, On the Brevity of Life, On the Happy Life, and On the Tranquillity of the Soul. The nine tragedies are Hercules Furens, Troades, Phoenissae, Medea, Phaedra, Oedipus, Agamemnon, Thyestes, and Hercules Oetaeus.