The Greek Way of Life. Marcus Aurelius 1.6
A good tutor helps charges with more than just academics. You can listen to me reading Marcus' thoughts on his tutor <here>.
Παρὰ
Διογνήτου τὸ ἀκενόσπουδον· καὶ τὸ
ἀπιστητικὸν τοῖς ὑπὸ τῶν τερατευομένων
καὶ γοήτων περὶ ἐπῳδῶν καὶ περὶ
δαιμόνων ἀποπομπῆς καὶ τῶν τοιούτων
λεγομένοις· καὶ τὸ μὴ ὀρτυγοτροφεῖν
μηδὲ περὶ τὰ τοιαῦτα ἐπτοῆσθαι· καὶ
τὸ ἀνέχεσθαι παρρησίας· καὶ τὸ
οἰκειωθῆναι φιλοσοφίᾳ καὶ τὸ ἀκοῦσαι
πρῶτον μὲν Βακχείου, εἶτα Τανδάσιδος
καὶ Μαρκιανοῦ· καὶ τὸ γράψαι διαλόγους
ἐν παιδί· καὶ τὸ σκίμποδος καὶ δορᾶς
ἐπιθυμῆσαι καὶ ὅσα τοιαῦτα τῆς
Ἑλληνικῆς ἀγωγῆς ἐχόμενα. 
From
Diognetus (†) I learned
to avoid spending time on trivial things. To distrust the utterances
of omen-readers and wizards, who talk of spells, turning spirits
away, and other such things. Not to feed quail (‡)
or be excited about such matters. I also learned from him to refrain
from speaking too frankly, and to be at home with philosophy; he took
me to listen to philosophers, first Bacchius, then Tandasis and
Marcianus. I also learned from him to write dialogues, as a boy. To
love the bedroll and animal-skin and all things pertaining to the
Greek way of life (*).   
---
(†)
The Historia Augusta records
that Diognetus instructed Marcus in the art of painting (§ 4: operam praeterea pingendo sub magistro Diogeneto dedit).
Apparently that lesson did not matter as much to the young man as
others. History shows that learning is often like this: we get more
from people, from their character and manner, than just a technical
skill-set. A young person wants mentors more than mastery of any
technical skill.
(‡) Ancient Mediterraneans used to catch quail (ὄρτυγες, coturnices) in the spring, feed them throughout the summer in enclosures (ὀρτυγοτροφεῖα), and then eat them in the fall. For more information, see Dalby, Food in the Ancient World,
s.v. quail.
(*) This makes me think of Odysseus' reception at the house of his swineherd Eumaeus (Odyssey 14.1-66, esp. lines 50-51: ἐστόρεσεν δ᾽ ἐπὶ δέρμα ἰονθάδος ἀγρίου αἰγός, αὐτοῦ ἐνεύναιον, μέγα καὶ δασύ).
(*) This makes me think of Odysseus' reception at the house of his swineherd Eumaeus (Odyssey 14.1-66, esp. lines 50-51: ἐστόρεσεν δ᾽ ἐπὶ δέρμα ἰονθάδος ἀγρίου αἰγός, αὐτοῦ ἐνεύναιον, μέγα καὶ δασύ).