Passage 8.42.8
μαρτυρεῖ δέ μοι τῷ λόγῳ· κατὰ γὰρ τὴν Ξέρξου διάβασιν ἐς τὴν Εὐρώπην Συρακουσῶν τε ἐτυράννει καὶ Σικελίας τῆς ἄλλης Γέλων ὁ Δεινομένους· ἐπεὶ δὲ ἐτελεύτησε Γέλων, ἐς Ἱέρωνα ἀδελφὸν Γέλωνος περιῆλθεν ἡ ἀρχή· Ἱέρωνος δὲ ἀποθανόντος πρότερον πρὶν ἢ τῷ Ὀλυμπίῳ Διὶ ἀναθεῖναι τὰ ἀναθήματα ἃ εὔξατο ἐπὶ τῶν ἵππων ταῖς νίκαις, οὕτω Δεινομένης ὁ Ἱέρωνος ἀπέδωκεν ὑπὲρ τοῦ πατρός.
My account is supported by evidence; for at the time of Xerxes' crossing into Europe, Gelon, son of Deinomenes, was ruling as tyrant over Syracuse and the rest of Sicily. When Gelon died, the sovereignty passed to his brother Hieron. However, Hieron died before he could dedicate to Olympian Zeus the votive offerings he had vowed in celebration of his victories with horses; thus Deinomenes, son of Hieron, made the dedication on behalf of his father.