History of the Peloponnesian War

As for the Thasians, who had been defeated in battle and were now besieged, they appealed to the Lacedaemonians and urged them to come to their aid by invading Attica.

This, unknown to the Athenians, they promised to do, and intended to keep their promise, but were prevented by the earthquake[*](Called "the great earthquake" in Thuc. 1.128.1.) which occurred at the time[*](464 B.C.) when both their Helots and the Perioeci of Thuria and Aethaea revolted and went to Ithome.[*](The Perioeci were the old inhabitants of the country, chiefly of Achaean stock, reduced to a condition of dependence, i.e. were not citizens, though not state—slaves as the Helots were.) Most of the Helots were the descendants of the early Messenians who had been enslaved of old,[*](Referring to the mythical time of the first Messenian war.) and hence were all called Messenians.

The Lacedaemonians, then, were involved in war with the rebels on Ithome; and so the Thasians, who were in the third year of the siege, came to terms with the Athenians, pulling down their walls and delivering over their ships, agreeing to pay forthwith whatever sum of money should be required of them and to render tribute in future, and, finally, giving up both the mainland and the mine.