Spartoi in Thebes 
Cadmus arrived in Thebes, Greece after following a cow at the urging of the oracle at Delphi, who instructed him to found a city wherever the cow should stop. Cadmus, wishing to sacrifice the cow, sent his men to a nearby spring to fetch water. The spring was guarded by a dragon, which slew many of the men before Cadmus killed it with his sword.
According to the Bibliotheca, the dragon was sacred to Ares. Athena gave Cadmus half of the dragon's teeth, advising him to sow them. When he did, fierce armed men sprang up from the furrows. Cadmus threw a stone among them because he feared them, and they, thinking that the stone had been thrown by one of the others, fought each other until only five of them remained: Echion, Udeus, Chthonius, Hyperenor and Pelorus. These five helped Cadmus to found the city of Thebes, but Cadmus was forced to be a slave to Ares for one year to atone for killing the dragon. At the end of the year, he was given Harmonia, the daughter of Aphrodite and Ares, to be his wife.
However, Hellanicus writes that only five Spartoi sprang up, omitting the battle between them. In his version, Zeus had to intervene to save Cadmus from the anger of Ares, who wished to kill him. Echion later married Agave, the daughter of Cadmus, and Pentheus their son succeeded Cadmus as king.
Spartoi in Colchis 
The other half of the dragon's teeth were planted by Jason at Colchis. Aeetes, the king of Colchis, had been given the teeth by Athena, and he forced Jason to sow them in order to win the golden fleece. Like Cadmus, Jason threw a stone among the spartoi to confuse them. The spartoi then began to fight each other over the stone. None survived the battle.
See also 
- Gantz, p. 467.
- Apollodorus. Bibliotheca, 3.4.
- Gantz, p. 468.
- Gantz, Timothy. Early Greek Myth. Baltimore: Johns Hopkins University Press, 1993.