Genre and place in the book. The sixth entry in the catalogue of debts, and a pivot for the whole of Book I and for the biography of Marcus as a whole. Where 01-05 (the pedagogue) sketched the everyday habitus of the child, 01-06 fixes the philosophical conversion of the adolescent: the moment when Marcus becomes "at home" (οἰκειωθῆναι) in philosophy and begins to wear the philosopher's cloak, to sleep on a hard pallet, and to write dialogues. Biographically this dates to about 132–133, when Marcus was eleven or twelve. After 01-06 the sequence of teachers is already philosophical: Junius Rusticus (01-07), Apollonius of Chalcedon (01-08), Sextus (01-09).

Who is Diognetus. SHA Marcus (ch. 4) calls him a teacher of painting: "studuit et picturae sub magistro Diogneto" ("he also studied painting under the teacher Diognetus"). But in 01-06 Marcus ascribes much more to him — the philosophical initiation itself. Two readings are possible: (a) Diognetus was a professional painter but intellectually close to the philosophical circle, who informally introduced Marcus to philosophy; (b) the SHA notice records only one aspect of his role, while his school affiliation was broader. Prosopographically Diognetus is scarcely attested: the modern view (Birley, Hadot, Hard) accepts that he was a figure of one of the philosophical schools (Platonist or Stoic; secure identification is lacking), active in Marcus's household during the early-adolescent period. More in the PERSONcard.

The structure of the passage. To Diognetus Marcus ascribes four connected transitions (in logical, not chronological, order):

1. A triple scepticism — against trifles, against miracle-workers, against quail-fighting.
2. Tolerance of παρρησία — the capacity to receive direct (not flattering) speech.
3. The conversion into philosophy — οἰκειωθῆναι φιλοσοφίᾳ + the sequence of teachers + the dialogues.
4. The Greek asceticism — the desire for the hard pallet and the animal skin, "and all the rest that goes with the Greek discipline."

The movement is from clearing (1) and openness (2) to formation (3) and practice (4). The paragraph structurally mirrors the classical Hadot pattern of conversion: epistemic scepticism → ethical practice → existential choice.

The triple scepticism.

1. τὸ ἀκενόσπουδον — literally "not-empty-seriousness," the refusal of serious attention to trifles (κενός — empty). It is not "not to be serious," but "not to be serious to no purpose" — the typical Hellenistic ethics of measured attention. Marcus will develop the thought in Med. 4.32 (on the great occupations of small people) and Med. 8.5 (on the sage who does not fuss).
2. τὸ ἀπιστητικὸν τοῖς ὑπὸ τῶν τερατευομένων καὶ γοήτων περὶ ἐπῳδῶν καὶ περὶ δαιμόνων ἀποπομπῆς καὶ τῶν τοιούτων λεγομένοις — "disbelief in what is said by miracle-workers and charlatans about incantations, the driving-out of daimones, and such things." Τερατευόμενοι are "wonder-workers" displaying the supernatural; γόητες are magicians, sorcerers. This is not atheism (Marcus was deeply religious — cf. the prayers at Med. 5.7, the thanksgiving at 01-17), but the drawing of a line between official cult and charlatanism. The second century AD is the golden age of magicians and oracles; the contemporary Lucian in Alexander the False Prophet and the Peregrinus documents exactly the same position of aristocratic scepticism toward such practices. The disposition is especially important for a future emperor: the state cult required support, but the cults of charlatans, persecution — or at least distance.
3. τὸ μὴ ὀρτυγοτροφεῖν μηδὲ περὶ τὰ τοιαῦτα ἐπτοῆσθαι — "not to breed quails and not to be aflutter for such things." Ὀρτυγοτροφία is the breeding of quails for fighting, a popular aristocratic sport of the second century (as cockfighting was later). Ἐπτοῆσθαι is literally "to be agitated as a bird"; the standard Stoic term for affective excitement, the synonym of πάθος. Two layers here: (a) the everyday — not to grow attached to a sport that demands passionate involvement; (b) the technical — not to let passion seize one in any such occupation. Rogovin's footnote ⁹ clarifies that quail-fighting was specifically a fashion; this links back to 01-05 (the refusal of the circus and gladiator factions) — Diognetus continues the same line of detachment from mass passions, but shifts it from a pedagogical position to a philosophical-psychological one.

Παρρησία. τὸ ἀνέχεσθαι παρρησίας — "to endure παρρησία," that is, direct, unflattering speech. Παρρησία is the classical Greek concept, technically "the freedom to say everything," socially the obligation of the citizen to voice the politically unpopular, philosophically the capacity of the pupil to receive criticism from the teacher. For a future emperor the virtue is politically and philosophically critical: surrounded by flatterers, he must be able not to close himself off to criticism. Foucault develops the theme in Le courage de la vérité (1984) as a central line in Hellenistic-Roman ethics: παρρησία is not the freedom to speak but the capacity to listen (the side at issue here in Marcus). This is the bridge to Junius Rusticus (01-07), to whom the principal ascription is that he pointed out Marcus's errors — that is, exercised παρρησία in the pedagogic mode.

Conversion: οἰκειωθῆναι φιλοσοφίᾳ. τὸ οἰκειωθῆναι φιλοσοφίᾳ — "to have been brought into οἰκείωσις with philosophy," to be made-at-home with philosophy. The verb οἰκειωθῆναι is the passive of οἰκειόω, a technical Stoic term (see DOGMAthe doctrine of οἰκείωσις): οἰκείωσις is the foundational mechanism of becoming-one's-own; for the Stoa it is the innate process by which the circle of "the own" expands from the body to the family, to the community, to humanity, to the cosmos. Marcus here describes the conversion to philosophy in exactly these Stoic terms: philosophy becomes for him "his own" (οἰκεία), an element of his own οἶκος. This is a technical Stoic word, and its choice in the first paragraph after the two "general" teachers (the pedagogue + Diognetus, still before Junius Rusticus) marks that Marcus identifies the moment of Diognetus's instruction as the philosophical conversion proper — long before the meeting with the formal Stoic teacher.

The three teachers. Marcus enumerates them: "first Bacchius, then Tandasis and Marcianus" (πρῶτον μὲν Βακχείου, εἶτα Τανδάσιδος καὶ Μαρκιανοῦ). These are three names weakly attested in the sources:

• Βάκχειος (PERSONcard) — most plausibly identified with Bacchius the Platonist, mentioned by Galen; more in the card.
• Τανδάσις (PERSONcard) — almost without attestation; the manuscript tradition gives "Τανδάσις," a minority reads "Θανδάσις."
• Μαρκιανός (PERSONcard) — also weakly attested; sometimes connected with known Marciani but without secure identification.

A correction to Rogovin's note. Rogovin's footnote ¹⁰ records a problematic seventeenth-century editorial tradition: Gataker and Casaubon, on the basis of the different names at SHA Marcus (ch. 2; the precise sub-sections to be verified against the Hohl Teubner edition [verify:hohl]), where the early tutors are listed as Trosius Aper, Pollio, Eutychius Proculus, Alexander, proposed identifying Bacchius with Eutychius, Tandasis with Andron, Marcianus with Mecianus. The modern consensus (Farquharson, Hadot, Hard) rejects this compromise on two grounds: (a) the teachers of that SHA list are grammarians and rhetoricians (Eutychius Proculus is a Latin grammarian; Alexander is the Greek grammarian), whereas the teachers of 01-06 are philosophers (οἰκειωθῆναι φιλοσοφίᾳ, διαλόγους ἐν παιδί) — different disciplines and, apparently, different people; (b) Capitolinus in SHA separately enumerates Marcus's philosophical teachers (chs. 2–3: Junius Rusticus, Apollonius, Sextus, Claudius Maximus, Cinna Catulus), and Bacchius, Tandasis, Marcianus are not in that list — because they belong to the earlier, adolescent period (under Diognetus, approximately early 130s), well before the formal Stoic education under Junius Rusticus. The manuscript reading is kept; the names remain weakly attested.

γράψαι διαλόγους ἐν παιδί. "To have written dialogues as a boy." This is a report of the lost early works of Marcus — philosophical dialogues of his adolescence. Not a single fragment, not even a title, survives. Context: writing philosophical dialogues was a standard school exercise in the Hellenistic tradition (Cicero describes the same for his own education); the mention of these dialogues is important as a marker of formal philosophical preparation — Marcus not only listened but himself worked in the genre. Biographically, this is the equivalent of Marcus's having gone through a fully realised philosophical διατριβή long before the formal Stoic education under Junius Rusticus.

Ἑλληνικὴ ἀγωγή: σκίμπους and δορά. τὸ σκίμποδος καὶ δορᾶς ἐπιθυμῆσαι καὶ ὅσα τοιαῦτα τῆς Ἑλληνικῆς ἀγωγῆς ἐχόμενα — "to have wanted the hard couch (σκίμπους) and the animal skin (δορά), and all the rest that belongs to the Greek discipline." Σκίμπους is a small couch, wicker or plank, without bedding; δορά the beast's skin (in place of bed-linen). This is the uniform of the Hellenistic philosopher of the Cynic-Stoic complexion — a marker of ascetic life, visible in society. Rogovin's footnote ¹¹ links this to SHA Marcus 2.6: from the age of twelve Marcus adopted the ascetic mode, slept on the floor, wore the philosopher's cloak (the pallium in place of the toga), and was stopped by his mother only when he began to fall ill. Ἑλληνική ἀγωγή is a technical term: "the Greek (i.e. philosophical) discipline / way of life," set against the Roman civilian norm. To take up Ἑλληνική ἀγωγή is to declare oneself publicly a philosopher, not merely a reader of philosophy. For a Roman aristocrat this was a socially marked choice (Seneca at Ep. 5.1–4 will complain that such a visible asceticism provokes hostility). For further development see 01-07 (where Junius Rusticus will teach Marcus not to parade this philosophical habitus).

The shape of the inheritance from Diognetus. If the pedagogue in 01-05 handed on the everyday habitus (detachment from mass passions, simplicity, not entering into the affairs of others), Diognetus adds the next layer: the philosophical habitus — scepticism of charlatanism, openness to παρρησία, formal philosophical preparation (teachers + dialogues), and a visible ascetic modus vivendi. This is the adolescent philosophical initiation, on which the adult doctrinal training under Junius Rusticus, Apollonius and Sextus will later be laid down. Between the two layers stands the characteristic Hellenistic-Roman distinction: first entry into the life of the philosopher (Diognetus), then entry into the school (the Stoa).

Parallels. SHA Marcus, ch. 2 — the canonical report of the adolescent ascesis of Marcus (the cloak, ground-sleeping, the maternal prohibition); SHA Marcus, ch. 4 — Diognetus as the painting teacher (the precise sub-sections to be verified against the Hohl Teubner edition [verify:hohl]). Med. 1.17 — thanks given to the gods for "coming into [a philosophical] perception" and for "not having advanced further in rhetoric" (which, for Marcus, was a piece of luck — otherwise he might have stopped at a rhetor's formation). Plut. De superstitione (in the Moralia) — the canonical Stoic critique of superstition (δεισιδαιμονία), parallel to the Marcus-Diognetus scepticism toward miracle-workers. Lucian, Alexander the False Prophet — the contemporary document of the same position of detachment from cultic γόητες. Epict. Diss., book 3 — Epictetus's treatise on the Cynic, the developed ideal of that Ἑλληνική ἀγωγή which the young Marcus here took up.