Meanwhile the Thasians being defeated in the field and suffering siege, appealed to Lacedaemon, and desired her to assist them by an invasion of Attica. Without informing Athens she promised and intended to do so, but was prevented by the occurrence of the earthquake, accompanied by the secession of the Helots and the Thuriats and Aethaeans of the Perioeci to Ithome. Most of the Helots were the descendants of the old Messenians that were enslaved in the famous war; and so all of them came to be called Messenians. So the Lacedaemonians being engaged in a war with the rebels in Ithome, the Thasians in the third year of the siege obtained terms from the Athenians by razing their walls, delivering up their ships, and arranging to pay the monies demanded at once, and tribute in future; giving up their possessions on the continent together with the mine.