Cadmus, founder of Thebes and slayer of the dragon of Ares

Cadmus is the legendary founder of Thebes, son of Agenor, king of Phoenicia, and brother of Europa. Sent to find his sister after Zeus carried her off, he gave up the search, followed a cow as Apollo’s oracle told him, killed the dragon of Ares, and built the citadel that took his name, the Cadmea. He married Harmonia with every god in attendance, and then watched his daughters and grandsons destroyed one after another. Cadmus is both the civilising hero of Boeotia and the first link in the chain that leads to Oedipus.

A prince on the road

When Europa vanished, Agenor sent his sons to find her and forbade them to return empty-handed. Cadmus left with his mother Telephassa; after long wanderings, which other traditions route through Rhodes and Thera, the two settled in Thrace, where Telephassa died (Apollodorus, 3.4.1). Cadmus then went to Delphi to ask where his sister was.

The oracle told him to stop looking. He was to follow a cow and found a city wherever it lay down from exhaustion. Among the herds of Pelagon in Phocis, Cadmus found a heifer with a white mark like a full moon on each flank (Pausanias, 9.12.1), and followed it across Boeotia until it sank down. That was the site of Thebes. Ancient writers even explained the name Boeotia as “cow country”, from bous.

The dragon of Ares and the Sown Men

To sacrifice the cow to Athena, Cadmus sent his companions to draw water from a nearby spring. It was guarded by a serpent, a son of Ares in most accounts, which killed most of them. Cadmus destroyed it, with a rock and then a spear in Ovid’s version (Metamorphoses, 3.28-98).

On Athena’s advice he sowed the serpent’s teeth. Armed men sprang from the soil: the Spartoi, “the sown”. Cadmus threw a stone among them; each blamed the man next to him and they cut each other down until five remained, Echion, Udaeus, Chthonius, Hyperenor and Pelorus (Apollodorus, 3.4.1). The survivors became the Theban aristocracy. Echion married Agave, Cadmus’ daughter, and fathered Pentheus.

The motif returns in the story of Jason. In Colchis, King Aeetes hands the hero the other half of the same dragon’s teeth, given to him by Athena, and makes him sow them (Apollonius of Rhodes, Argonautica, 3.1176-1187). The founding of Thebes and the ordeal for the Golden Fleece literally grow from the same seed.

Killing the dragon had a price. Cadmus had to serve Ares for a “great year”, eight ordinary years, to be cleansed (Apollodorus, 3.4.2). Euripides keeps that spilled blood in view at the threshold of Theban history: the chorus of the Phoenician Women recalls the cow, the spring and the dragon at length, just as Oedipus’ sons are about to kill each other (638-675).

The wedding of Cadmus and Harmonia

When his service ended, Athena gave Cadmus the kingship and Zeus gave him a wife: Harmonia, daughter of Ares and Aphrodite (Hesiod, Theogony, 933-937). This is one of only two mortal weddings attended by all the gods, the other being that of Peleus and Thetis. Pindar pairs the two bridegrooms as the most fortunate men who ever lived, then reminds his audience that their happiness did not last (Pythian 3.88-99). Theognis records what the Muses sang at the feast: “What is beautiful is dear; what is not beautiful is not dear” (15-18).

Among the wedding gifts were a robe and a necklace made by Hephaestus. The necklace passed down the generations as an heirloom of disaster: Polynices used it to bribe Eriphyle into sending her husband Amphiaraus on the expedition of the Seven against Thebes.

A family marked for disaster

The couple had four daughters and a son (Hesiod, Theogony, 975-978; Apollodorus, 3.4.2), and nearly all met a terrible end:

• Semele, loved by Zeus, was burned to death by his lightning while carrying Dionysus;
• Ino nursed the infant Dionysus, was driven mad by Hera, and leapt into the sea with her son Melicertes, becoming the sea goddess Leucothea who later rescues Odysseus from shipwreck (Odyssey, 5.333-335);
• Autonoe was the mother of Actaeon, torn apart by his own hounds after seeing Artemis bathing;
• Agave, in a Bacchic frenzy, tore her own son Pentheus to pieces for resisting the god’s worship (Euripides, Bacchae);
• Polydorus, the son, was the grandfather of Laius and so the great-grandfather of Oedipus.

Founded on a killing, Thebes became Greek myth’s city of family catastrophe.

Illyria, serpents and the Isles of the Blessed

In old age Cadmus left Thebes with Harmonia and went to the Encheleans in Illyria, whom he led to victory and ruled. Then the pair were turned into serpents. In the Bacchae, Dionysus announces this fate to his grandfather, adding that Ares will one day settle them “in the land of the blessed” (1330-1339). Apollodorus says Zeus sent them to the Elysian Fields (3.5.4), and Pindar places Cadmus in the Isles of the Blessed alongside Peleus and Achilles (Olympian 2.78).

Ovid makes the scene intimate. Worn down by grief, Cadmus wonders whether the serpent he killed was sacred, and asks to become one himself if that is the penalty. His body lengthens and grows scales, and Harmonia, holding him, begs to share his fate (Metamorphoses, 4.563-603). The founder ends as the creature he had to kill to found.

The hero of letters

For Herodotus, Cadmus did more than build a city. The Phoenicians who came with him taught the Greeks the alphabet, which is why Greeks called letters phoinikeia grammata. Herodotus says he saw for himself, in the sanctuary of Ismenian Apollo at Thebes, tripods inscribed in “Cadmeian letters” (5.57-61). He also credits Cadmus and his followers with passing the worship of Dionysus to the seer Melampus (2.49).

Here legend meets history: the Greek alphabet really is an adaptation of Phoenician script. Cadmus let the Greeks acknowledge a cultural debt to the East while turning its bearer into a hero of their own past.

Further reading

For the sister whose disappearance starts the story, read Europa, then her son Minos. For Cadmus’ descendants, see Semele and Dionysus, then the Labdacid line through Laius, Oedipus and Antigone. For the dragon’s teeth motif, see Jason and the story of Jason and the Golden Fleece.