Passage 1.29.8
πολεμοῦντος Κασσάνδρου καὶ οἱ συμμαχήσαντές ποτε Ἀργείων. πραχθῆναι δὲ οὕτω σφίσι τὴν πρὸς Ἀργείους λέγουσι συμμαχίαν· Λακεδαιμονίοις τὴν πόλιν τοῦ θεοῦ σείσαντος οἱ εἵλωτες ἐς Ἰθώμην ἀπέστησαν, ἀφεστηκότων δὲ οἱ Λακεδαιμόνιοι βοηθοὺς καὶ ἄλλους καὶ παρὰ Ἀθηναίων μετεπέμποντο· οἱ δέ σφισιν ἐπιλέκτους ἄνδρας ἀποστέλλουσι καὶ στρατηγὸν Κίμωνα τὸν Μιλτιάδου. τούτους ἀποπέμπουσιν οἱ Λακεδαιμόνιοι πρὸς ὑποψίαν·
While Cassander was at war, the Athenians had also formed an alliance with the Argives at that time. They recount that their alliance with the Argives had come about in the following manner: after the god had shaken Sparta with an earthquake, the Helots revolted and withdrew to Ithome. On account of this revolt, the Spartans sent entreaties for help, both to others and to Athens. The Athenians dispatched chosen warriors under the leadership of Cimon, son of Miltiades; the Spartans, however, dismissed them out of mistrust.