Passage 9.6.3
ὕστερον μέντοι καὶ Θηβαίοις νίκη κατʼ Ἀθηναίων ἐπὶ Δηλίῳ τῷ Ταναγραίων ἐγένετο, καὶ Ἱπποκράτης τε ὁ Ἀρίφρονος, ὃς στρατηγὸς ἦν Ἀθηναίοις, καὶ τῆς ἄλλης στρατιᾶς τὸ πολὺ ἔπεσε. Λακεδαιμονίοις δὲ παραυτίκα μὲν ἀπελθόντος τοῦ Μήδου καὶ ἄχρι τοῦ Πελοποννησίων πρὸς Ἀθηναίους πολέμου τὰ ἐκ Θηβῶν εἶχεν ἐπιτηδείως· διαπολεμηθέντος δὲ τοῦ πολέμου καὶ Ἀθηναίοις καταλυθέντος τοῦ ναυτικοῦ, μετʼ οὐ πολὺ Θηβαῖοι μετὰ Κορινθίων ἐς τὸν πρὸς Λακεδαιμονίους πόλεμον προήχθησαν.
Later, however, the Thebans also gained a victory over the Athenians at Delium in the territory of Tanagra; here Hippocrates, son of Ariphron, who was the general of the Athenians, fell, along with the greater part of the army. For the Lacedaemonians, immediately after the departure of the Persian and until the war between the Peloponnesians and Athenians, relations with Thebes were favorable. But once this war had been fought out and the naval power of Athens destroyed, the Thebans, not long after, entered into war against the Lacedaemonians alongside the Corinthians.