Aristophanes

Clouds (comedy) 423 B.C.

Aristotle

Metaphysics (philosophical treatise)

Rhetoric (philosophical treatise)

Plato

Protagoras (dialogue)

Meno (dialogue)

Apology (account of Socrates's trial)

Crito (dialogue)

Phaedo (dialogue)

Xenophon

Memorabilia (memoirs)

^* As Socrates's philosophical thought is known only through secondary sources, these are listed here. While exact composition dates for most of the works are unknown, the chronological order of Plato's works has been determined by critics and therefore his works have been listed in chronological order.