Passage 3.10.5
διέβη δὲ καὶ ἐς Ἰταλίαν ὕστερον Ταραντίνοις βαρβάρων πόλεμον συνδιοίσων σφίσιν ὁμόρων· καὶ ἀπέθανέ τε αὐτόθι ὑπὸ τῶν βαρβάρων καὶ αὐτοῦ τὸν νεκρὸν ἁμαρτεῖν τάφου τὸ μήνιμα ἐγένετο ἐμποδὼν τὸ ἐκ τοῦ Ἀπόλλωνος. τοῦ δὲ Ἀρχιδάμου τούτου τὸν μὲν πρεσβύτερον παῖδα Ἆγιν κατέλαβεν ἀποθανεῖν Μακεδόσιν ἐναντία καὶ Ἀντιπάτρῳ μαχεσάμενον, Εὐδαμίδας δὲ ὁ νεώτερος Λακεδαιμονίοις ἐβασίλευσεν ἄγουσιν εἰρήνην. τὰ δὲ ἐς Ἆγιν τὸν Εὐδαμίδου καὶ ἐς Εὐρυδαμίδαν τὸν Ἄγιδος ὡς ἔσχεν, ἤδη μοι καὶ τάδε ἡ Σικυωνία συγ γραφὴ διεξῄει.
Afterwards he crossed also into Italy to assist the Tarentines in a war against neighboring barbarians. There he died at the hands of the barbarians, and the wrath of Apollo prevented his corpse from receiving burial. Concerning this Archidamus, his elder son Agis met death fighting against Antipater and the Macedonians, whereas his younger son, Eudamidas, reigned over the Lacedaemonians while they enjoyed peace. The further events involving Agis, son of Eudamidas, and Eurydamidas, son of Agis, have already been related in my account of Sicyon.