Source Verification: Cadmus and the Dragon

Every claim below is either what a named ancient source attests, in its own line or section, or a point where the sources themselves disagree.

What the Sources Attest

Who was Cadmus in Greek mythology?

Cadmus was the Phoenician prince who founded Thebes. Apollodorus makes him a son of Agenor and Telephassa and a brother of Europa. He followed a cow to the site of the city, killed the dragon guarding the spring of Ares, and sowed its teeth to raise the armed Sparti. His whole life is on the Cadmus page.

Source: Apollodorus, Library 3.4.1

Who did Cadmus marry?

Cadmus married Harmonia, daughter of Aphrodite and Ares. Apollodorus says Zeus gave her to him after his servitude to Ares for the dragon's death, and that all the gods left the sky to celebrate the marriage in the Cadmea. Cadmus gave her a robe and the necklace wrought by Hephaestus.

Source: Apollodorus, Library 3.4.2

Who was Cadmus's father in Greek mythology?

His father was Agenor, whom Ovid calls a king. Apollodorus says Agenor was a son of Poseidon and Libya, went to Phoenicia, married Telephassa, and had a daughter Europa and three sons, Cadmus, Phoenix and Cilix. It was Agenor who sent his sons to search for the vanished Europa.

Source: Apollodorus, Library 3.1.1

Who was Cadmus' daughter?

Cadmus had four daughters, Autonoe, Ino, Semele and Agave, and a son Polydorus. Apollodorus adds that Ino married Athamas, Autonoe married Aristaeus, and Agave married Echion. The story of Semele is on her own page.

Source: Apollodorus, Library 3.4.2

Where Accounts Differ

why-cadmus-left-home
who-fetched-the-water
how-the-dragon-died
dragon-child-of-ares
athena-or-jupiter-sacrifice
how-the-sown-men-died
servitude-to-ares

Why Cadmus reached Boeotia differs. Ovid, Metamorphoses 3.1-94, has Agenor threaten him with exile if he returns without Europa. Apollodorus, Library 3.4.1, has him settle in Thrace and go to Delphi only after Telephassa's death, where the god tells him to give up the search.
Who fetched the water differs. Apollodorus, Library 3.4.1, and Ovid, Metamorphoses 3.1-94, send companions and lose them to the dragon. Euripides, Phoenissae 638-675, has Cadmus come to draw the water himself.
The weapon differs. Ovid, Metamorphoses 3.1-94, has a millstone fail, then a javelin and a lance, ending with the dragon pinned to an oak. Euripides, Phoenissae 638-675, says he destroyed it with a jagged stone. Apollodorus, Library 3.4.1, names no weapon.
The dragon's status differs. Apollodorus, Library 3.4.1, says some thought it a child of Ares. Ovid, Metamorphoses 3.1-94, calls it sacred to Mars. Euripides, Phoenissae 638-675, calls it Ares's murderous dragon.
The intended sacrifice differs. Apollodorus, Library 3.4.1, says Cadmus wished to sacrifice the cow to Athena. Ovid, Metamorphoses 3.1-94, says he prepared a sacrifice to Jupiter.
How the sown men died differs. Apollodorus, Library 3.4.1, says a chance brawl or ignorance, and cites Pherecydes for Cadmus throwing stones among them. Ovid, Metamorphoses 3.95-137, has one warrior cry against civil war and the rest fall in mutual slaughter. Euripides, Phoenissae 638-675, only says that slaughter returned them to the earth.
Only Apollodorus, Library 3.4.2, gives the eternal year of service to Ares. In the Ovid passage read here, an unseen voice instead foretells that Cadmus will become a serpent.

Sources

Primary sources

Ovid, Metamorphoses 3.1-94
Ovid, Metamorphoses 3.95-137
Apollodorus, Library 3.1.1
Apollodorus, Library 3.4.1
Apollodorus, Library 3.4.2
Euripides, Phoenissae 638-675
Pausanias, Description of Greece 9.12.1
Pausanias, Description of Greece 9.12.2
Ovid, Metamorphoses 3.95-98