Passage 9.23.3
ἀρχὴ μὲν Πινδάρῳ ποιεῖν ᾄσματα ἐγένετο τοιαύτη· εὐδοκιμοῦντα δὲ αὐτὸν ἤδη ἀνὰ πᾶσαν τὴν Ἑλλάδα ἐς πλέον δόξης ἦρεν ἡ Πυθία ἀνειποῦσα Δελφοῖς, ὁπόσων ἀπήρχοντο τῷ Ἀπόλλωνι, μοῖραν καὶ Πινδάρῳ τὴν ἴσην ἁπάντων νέμειν. λέγεται δὲ καὶ ὀνείρατος ὄψιν αὐτῷ γενέσθαι προήκοντι ἐς γῆρας· ἐπιστᾶσα ἡ Περσεφόνη οἱ καθεύδοντι οὐκ ἔφασκεν ὑμνηθῆναι μόνη θεῶν ὑπὸ Πινδάρου, ποιήσειν μέντοι καὶ ἐς αὐτὴν ᾆσμα Πίνδαρον ἐλθόντα ὡς αὐτήν.
Such was the occasion of Pindar's first composition of poetry; but when his fame already extended throughout all of Greece, it was further enhanced by the oracle at Delphi, which commanded the Delphians that of all offerings dedicated to Apollo, a portion equal to the god's own should be assigned likewise to Pindar. It is also said that, when Pindar was advanced in years, a vision appeared to him in sleep. Persephone stood beside him as he slept and complained of having alone among the gods failed to receive praise from him; however, she declared that Pindar, when he came at last to her, would yet compose a song in her honor.