History of the Peloponnesian War

And the Dorians, who are the mother nation to the Lacedaemonians, sent their ambassadors likewise with him with the same requests; for they also were infested with war from the same Oetaeans.

Upon audience of these ambassadors the Lacedaemonians concluded to send out a colony, both intending the reparation of the injuries done to the Trachinians and to the Dorians and conceiving withal that the town would stand very commodiously for their war with the Athenians, inasmuch as they might thereby have a navy ready, where the passage was but short, against Euboea; and it would much further their conveyance of soldiers into Thrace. And they had their mind wholly bent to the building of the place. First, therefore, they asked counsel of the oracle in Delphi.