History of the Peloponnesian War

About this time the Lacedaemonians founded their colony of Heraclea in Trachis, their object being the following.

The Malians form in all three tribes, the Paralians, the Hiereans, and the Trachinians. The last of these having suffered severely in a war with their neighbors the Oetaeans, at first intended to give themselves up to Athens; but afterwards fearing not to find in her the security that they sought, sent to Lacedaemon, having chosen Tisamenus for their ambassador.

In this embassy joined also the Dorians from the mother country of the Lacedaemonians, with the same request, as they themselves also suffered from the same enemy.

After hearing them, the Lacedaemonians determined to send out the colony, wishing to assist the Trachinians and Dorians, and also because they thought that the proposed town would lie conveniently for the purposes of the war against the Athenians. A fleet might be got ready there against Euboea, with the advantage of a short passage to the island; and the town would also be useful as a station on the road to Thrace. In short, everything made the Lacedaemonians eager to found the place.

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.