Cadmus fighting the dragon portrayed on a Greek urn.
Cadmus was one of the great heroes of Greek mythology, the son of Agenor and Telephassa, and brother of Europa.
When the latter was carried off by Zeus, Cadmus was sent by Agenor in quest of her, with orders not to come back emty-handed. The search was in vain, and the oracle at Delphi told Cadmus to give up and instead follow a certain cow he'd meet, and build a city where it lay down. He found the cow in Phocis, followed her to Boeotia, and there built the city of Thebes. Intending to sacrifice the cow to Athena, he sent some men to the well of Ares close by for water, but they were killed by the dragon, son of Ares, who guarded it. Cadmus then slew the dragon, and sowed the creature's teeth in the ground. From these immediately sprang up armed men who set upon and slew each other until only five were left; these survivors became the progenitors of the Theban families.
To Cadmus (possibly a Phoenician name) was ascribed the introduction into Greece of the alphabet.