History of the Peloponnesian War

After first consulting the god at Delphi and receiving a favorable answer, they sent off the colonists, Spartans and Perioeci, inviting also any of the rest of the Hellenes who might wish to accompany them, except Ionians, Achaeans, and certain other nationalities; three Lacedaemonians leading as founders of the colony, Leon, Alcidas, and Damagon.

The settlement effected, they fortified anew the city, now called Heraclea, distant about four miles and a half from Thermopylae and two miles and a quarter from the sea, and commenced building docks, closing the side towards Thermopylae just by the pass itself, in order that they might be easily defended.