Invincibility through self-collection. The classic formula of Stoic freedom: the TERMruling faculty becomes "unconquerable" (ἀκαταμάχητον), "coiled into itself" (εἰς ἑαυτὸ συστραφέν) and "content with itself" (ἀρκεσθῇ ἑαυτῷ) — doing nothing it does not will. Marcus adds a subtlety: it is impregnable even when it resists "unreasonably" (ἀλόγως); all the more when it judges TERM"with reason" (μετὰ λόγου) and circumspectly. A refusal (even a stubborn one) already shows that the external has no power over assent; a reasoned refusal makes that power complete.

A citadel free of passions. Hence the image central to Hadot, the inner citadel: EXERCISE"the acropolis (ἀκρόπολις) is the mind free of passions (ἐλευθέρα παθῶν διάνοια)". A man has no stronghold "more secure" (ὀχυρώτερον): once he has fled into it, he is henceforth "unassailable" (ἀνάλωτος). This refuge is not in the wilds nor in retirement but in the DOGMAruling part itself (cf. 4.3 — "nowhere either with more quiet or more freedom from trouble does a man retire than into his own soul"; 7.28 — "Retire into thyself"). The close is a stark fork: he who has not seen this citadel is "ignorant" (ἀμαθής); he who has seen it but does not flee to it is "unfortunate" (ἀτυχής): knowledge without the refuge is useless. The governing discipline is assent (to collect the mind into itself), the sustaining one desire (not to do the unwilled).