Origin and designation. The standard designation in the sources is Ἀπολλώνιος ὁ Χαλκηδόνιος ("Apollonius of Chalcedon"), from Χαλκηδών — the city in Bithynia on the Asiatic side of the Bosporus, opposite Byzantium. SHA Pius 10.4 and SHA Marcus 3.3 in different manuscript branches also give the variant "Νικομηδεύς" ("of Nicomedia," from Nicomedia, the chief city of the same province). The modern consensus (Birley, Hadot, Hard, Farquharson): this is one and the same man; the confusion of the variants goes back to the proximity of the two cities and to a common Asiatic-Bithynian tradition; "of Nicomedia" perhaps refers to the place of his teaching, "of Chalcedon" to the place of birth.

Career at Athens. Before the summons to Rome, Apollonius taught at Athens — which in the second century meant belonging to one of the principal successor schools of the Stoa (the old Stoa of Zeno and Chrysippus no longer existed as an institutional school, but Athens remained the centre of philosophical instruction, especially after Hadrian's reforms, which established state-funded chairs of philosophy at Athens). On indirect evidence (Galen, Lucian) Apollonius was among the most financially successful philosophical teachers of his generation, which in second-century Athens meant paying pupils and a position of some influence.

The summons to Rome. Around 138–140 (shortly after the accession of Antoninus Pius and the adoption of Marcus) Antoninus Pius specifically summoned Apollonius from Athens to Rome to take charge of the education of the adopted heir. This is a characteristic Antonine practice: Hellenistic-philosophical teachers of high rank were imported to Rome for the instruction of the heirs and of the senatorial elite. Apollonius arrived in Rome, it seems, accompanied by a group of disciples (Lucian's "Argonauts" — see below).

The anecdote of the refusal to appear at the palace. SHA Pius 10.4 reports: when Antoninus Pius wished to see Apollonius at his residence (presumably the Tibur villa), Apollonius answered that "it is not for the teacher to go to the pupil, but for the pupil to come to the teacher" (the sermo magistri ad discipulum, non discipuli ad magistrum). Antoninus Pius, on one version of the anecdote, laughed and went himself; on another, he turned the matter aside with the jest: "It was easier for him to come from Athens to Rome than from his lodging to the palace." This anecdote is the most famous about Apollonius, and characterises his Stoic dignity (or, on an unfriendly reading, his pride).

The satirical portrait in Lucian. Lucian, Demonax 31: Demonax meets in the street Apollonius going at the head of a retinue of disciples to Pamphylia (that is, with his own group of παίδες for paid instruction), and remarks: "There goes Apollonius with his Argonauts" (that is, gathered for the sake of the "golden fleece" — the fee). It is a satirical thrust against professional public philosophy for pay — a characteristic Cynic-Demonactean move against the entire "Stoic establishment" of the second century. The testimony to the paid character of Apollonius's teaching is reliable (Lucian here is not inventing the practice but only re-evaluating it ethically); the question of what this says about Apollonius's actual character is open. Marcus in 01-08 is the internal witness, directly correcting Lucian's external picture: "a man who counted his skill in transmitting doctrines as the least of his καλά."

Biographical details from Marcus himself. 01-08 is the unique text in which Marcus, as a direct witness, reports biographical details about Apollonius:

• Sharp pains — Apollonius bore them while remaining ἀεὶ ὅμοιος.
• The loss of a son — Apollonius lost a child during Marcus's tutelage, and Marcus saw his reaction.
• A long illness — Apollonius was ill for a long time and so remained ἀεὶ ὅμοιος.

These three personal testimonies are unique: no other source on Apollonius preserves such details. They are known exclusively from Marcus, and are significant as internal evidence (against the external evidence of the SHA and of Lucian).

• 01-08 — the principal, developed portrait of Apollonius; the unique text with the personal biographical details (loss of a son, long illness).
• 01-17 — the thanksgiving to the gods for "having received good teachers"; Apollonius implicitly among them.

• SHA Pius 10.4 — the anecdote of the refusal to appear at the palace first; the key prosopographical testimony.
• SHA Marcus 3.3 — Apollonius among Marcus's principal philosophical teachers.
• Lucian, Demonax 31 — the satirical portrait of "Apollonius and his Argonauts"; the obverse of the character, valuable as external testimony.
• PIR² A 933 — the standard prosopographical entry.
• A. Birley, Marcus Aurelius: A Biography, rev. ed., Routledge, 2000, ch. 3 ("Education") and passim — the reconstruction of Apollonius's role and his summons to Rome.
• A. S. L. Farquharson, The Meditations of the Emperor Marcus Antoninus, Oxford 1944, vol. II, ad 1.8 — the standard philological commentary.
• R. Hard, Marcus Aurelius: Meditations, OWC, Oxford 2011, notes ad 1.8.
• P. Hadot, The Inner Citadel, tr. M. Chase, Harvard 1998, ch. 2–3 — the general reconstruction of Marcus's educational biography, with discussion of Apollonius as "παράδειγμα ζῶν."