Plutarch, On the Fortune of Alexander 340a
Plutarch is in the middle of admiring Alexander for his ability to keep top secret matters secret. In illustration of this he recounts a rather sweet story about Alexander and his boyfriend Hephaestion:
λέγεται γὰρ ὅτι καὶ τῆς μητρὸς ἀπόρρητον ἐπιστολὴν λύσαντος αὐτοῦ καὶ σιωπῇ πρὸς ἑαυτὸν ἀναγιγνώσκοντος, Ἡφαιστίων ἀτρέμα παραβάλλων τὴν κεφαλὴν συνανεγίγνωσκεν· ὁ δὲ κωλῦσαι μὲν οὐχ ὑπέμεινεν, ἐξελὼν δὲ τὸν δακτύλιον προσέθηκε τὴν σφραγῖδα τῷ στόματι τοῦ Ἡφαιστίωνος.
It is said that, when Alexander had opened a confidential letter from his mother and was reading it to himself in silence, Hephaestion gently put his head beside his and read along with him. Alexander could not bear to stop him, but taking off his ring pressed the seal onto Hephaestion’s mouth.
This passage is one of the various pieces of evidence in the ‘silent reading’ debate: did people in the ancient world generally read out loud to themselves, rather than reading silently as we normally do? I shall point you to some further discussion on the QI forums. I came across this passage the other day in Jocelyn Penny Small’s Wax Tablets of the Mind, London & New York 1997, p.22.