The Phaedo (Greek: Φαίδων) is a famous dialogue written sometime in the early 4th-century BCE by the Greek philosopher Plato. The dialogue occurs in Socrates' prison cell, before he is to be executed by drinking hemlock. In it, he seeks to prove the immortality of the soul, the existence of the afterlife, and immorality of suicide. This has made the piece influential among Christian scholars, although the beliefs in reincarnation and the transmigration of souls are given favorable treatment. A great deal of the dialogue is given to discussion of Plato's well-know "theory of forms."