Plato, son of Ariston, an Athenian; in youth a follower of Socrates, and after his execution (399 BCE) — travels (Megara, Egypt by tradition, three Sicilian ventures with their unhappy experiments at the Syracusan court) and the founding of the Academy (c. 387 BCE) — the Mediterranean's first enduring philosophical school, which lasted nine centuries until Justinian's edict (529 CE). The corpus of ~28 genuine dialogues survives complete — a unique case for an ancient philosopher. The chief biographical source is DL III; the Seventh Letter (of disputed authenticity) is a self-testimony about the Sicilian ventures.

For the Stoics Plato is at once ancestor and opponent. Ancestor — through Socrates: the line "virtue is knowledge, vice is ignorance," the care of the soul, the image of the philosopher at his post (Phd. 62b) passed straight into the Stoa; the very tripartition of philosophy (logic—physics—ethics) is of Academic origin (Xenocrates). Opponent — in ontology: against the transcendent Forms the Stoics set the immanent corporeal Logos, and against the soul's immortality — its dissolution into the Whole.

Marcus's relation is practical, without school polemic: Plato is a supplier of exercises and formulae. His favourite Platonic motifs: the scale of the soul that embraces "all time and all being" (Resp. 486a — the core of the view from above); the soldier at his post who does not quit the line for fear of death (Apol. 28d); contempt for mere length of life (Gorg. 512d–e). Plato's political idealism, meanwhile, Marcus soberly cuts away: "do not hope for Plato's Republic" (9.29) — to the emperor the city of ideas is not a programme but a measure of modest expectations.

• 07-35 — a verbatim excerpt of Resp. VI 486a: to the soul contemplating "all time and all being" human life seems nothing great — "then death, too, is not terrible." Opens Book VII's Plato series.
• 07-44 — Apol. 28b: for a man of any worth the reckoning is not "life or death" but only "is what I do just."
• 07-45 — Apol. 28d–29a: where a man has posted himself (or been posted by his commander), there he must stay amid danger, counting neither death nor anything else before disgrace.
• 07-46 — Gorg. 512d–e: not to cling to length of life but leave that to god, trusting that "no one escapes his destiny," and to consider instead how best to live the span allotted.
• 07-63 — "every soul is deprived of truth against its will" (φησίν): a thesis going back to Plato (~ Sophist 228c / the Socratic "no one errs willingly"); the ground of gentleness.
• 07-48 — the "Platonic" dictum on viewing earthly things from a height (herds, armies, weddings, law-courts): not found in the extant dialogues — either a paraphrase or a lost source; in spirit — Resp. 486a plus Theaet. 173e–174a (the philosopher surveying all from above).
• 09-29 — "do not hope for Plato's Republic": be content with the smallest step forward.
• 10-23 — the quotation about the "fold upon the mountain" (Theaet. 174d–e): in the philosopher's eyes the great landowner is indistinguishable from a shepherd fencing a fold and milking "bleatings"; the argument against changing place.

• Diogenes Laertius III — biography and catalogue
• The Platonic corpus — Resp. VI 486a; Apol. 28b–29a; Gorg. 512d–e; Phd. 62b; Theaet. 173c–176a
• J. Annas, Platonic Ethics, Old and New, Ithaca 1999
• P. Hadot, The Inner Citadel, Cambridge (MA) 1998 — on Book VII's Plato quotations and the "view from above"
• A. S. L. Farquharson, The Meditations of the Emperor Marcus Antoninus, Oxford 1944 — commentary ad loc.