What is "cadmean victory"

Cadmean \Cad*me"an\ (k[a^]d*m[=e]"an),

1. [L. Cadmeus, Gr. Kadmei^os, from Ka`dmos (L. Cadmus), which name perhaps means lit. a man from the East; cf. He

2. qedem east.] Of or pertaining to Cadmus, a fabulous prince of Thebes, who was said to have introduced into Greece the sixteen simple letters of the alphabet -- [alpha], [beta], [gamma], [delta], [epsilon], [iota], [kappa], [lambda], [mu], [nu], [omicron], [pi], [rho], [sigma], [tau], [upsilon]. These are called Cadmean letters.

   Cadmean victory, a victory that damages the victors as much as the vanquished; probably referring to the battle in which the soldiers who sprang from the dragon's teeth sown by Cadmus slew each other. Similar to a Pyhrric victory.

c.1600, "victory involving one's own ruin," translating Greek Kadmeia nike, from Cadmus (Greek Kadmos), legendary founder of Thebes in Boeotia and bringer of the alphabet to Greece. Probably a reference to the story of Cadmus and the "Sown-Men," who fought each other till only a handful were left alive. Compare Pyrrhic (adj.1).

n. A victory that damages the victors as much as the vanquished.

A Cadmean victory is a reference to a victory involving one's own ruin, from Cadmus (Greek: Kadmos), the legendary founder of Thebes in Boeotia and the mythic bringer of script to Greece. On seeking to establish the city, Cadmus required water from a spring guarded by a water-dragon similar to the Lernaean Hydra. He sent his companions to slay the dragon, but they all perished. Although Cadmus eventually proved victorious, the victory cost the lives of those who were to benefit from the new settlement.

The phrase "Cadmean victory" has been largely displaced in popular use by the somewhat similar expression "to win a battle but lose the war".