[2] He appears in Plato's Phaedo as a main discussion partner of Socrates alongside Cebes, as well as Crito,[3] Phaedrus,[4] and Epistle XIII.
[5] In addition to the references in Plato and Xenophon, Diogenes Laërtius mentions Simmias as the author of 23 brief dialogues, now lost, including On Philosophy and On Music.
[6] Simmias appears as a character in Plutarch's De Genio Socratis section of the Moralia.
[7] A pseudepigraphic letter from Xenophon to Simmias and Cebes is included in the Cynic epistles attributed to Socrates' followers.
[1] Two short works are also attributed to him in the Greek Anthology, a couplet on Sophocles and an epitaph on Plato.