Passage 1.27.8
ὅδε μὲν τῶν λόγων πρῶτος ἐς αὐτόν ἐστι Τροιζηνίοις· ὁ δὲ ἐπὶ τούτῳ, κρηπῖδας Αἰγέα ὑπὸ πέτρᾳ καὶ ξίφος θεῖναι γνωρίσματα εἶναι τῷ. παιδὶ καὶ τὸν μὲν ἐς Ἀθήνας ἀποπλεῖν, Θησέα δέ, ὡς ἕκτον καὶ δέκατον ἔτος ἐγεγόνει, τὴν πέτραν ἀνώσαντα οἴχεσθαι καὶ τὴν παρακαταθήκην τὴν Αἰγέως φέροντα. τούτου δὲ εἰκὼν ἐν ἀκροπόλει πεποίηται τοῦ λόγου, χαλκοῦ πάντα ὁμοίως πλὴν τῆς πέτρας·
This is the first of the traditions held concerning him by the Troezenians. The one following it is that Aegeus placed sandals and a sword under a rock as tokens for his child, and sailed away to Athens; and that Theseus, when he reached his sixteenth year, pushed the rock aside, departed, and carried with him the deposit left by Aegeus. A representation of this story has been made on the Acropolis; all of it is of bronze alike, except the rock.