Simmias the Theban was a wealthy member of
Socrates' close circle of friends. Originally
a student of the Italian Pythagorean philosopher,
Philolaus, he later became an associate of
Socrates and was present on the day of his death.
On that day the topic of discussion was the immortality of the soul (how
appropriate), a dialogue that is recorded in
Phaedo. In it Simmias articulates the
Pythagorean doctrine of the soul. In another
Platonic dialogue, the Phaedrus, Simmias
is praised highly for his philosophical abilities.