A Cadmean victory (Greek: καδμεία νίκη, romanized: kadmeía níkē) 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.
- Liddell, Henry George (Compiler), Scott, Robert (Compiler), Jones, Henry Stuart (Editor), McKenzie, Roderick. A Greek-English Lexicon, 9th ed. New York: Oxford University Press, 1995.
- Howatson, M. C. (Ed.) The Oxford Companion to Classical Literature, 2nd ed. New York: Oxford University Press, 2006. p. 105.
- Morford, Mark P. O. & Lenardon, Robert J., Classical Mythology, 7th ed. New York: Oxford University Press, 2002. p. 4.