An identically composed trio had other names at Samothrace, according to Diodorus Siculus: Electra and her two sons, Dardanos and Eetion or Iasion. There was a fourth figure, Electra's daughter, Harmonia, whom Cadmus took away as a bride, as Zeus had abducted Europa. The wedding was the first celebrated on Earth to which the gods brought gifts, according to Diodorus and dined with Cadmus and his bride. Founder of Thebes Cadmus came in the course of his wanderings to Delphi, where he consulted the oracle. He was ordered to give up his quest and follow a special cow, with a half moon on her flank, which would meet him, and to build a town on the spot where she should lie down exhausted. The cow was given to Cadmus by Pelagon, King of Phocis, and it guided him to Boeotia, where he founded the city of Thebes. Intending to sacrifice the cow to Athena, Cadmus sent some of his companions, Deioleon and Seriphus to the nearby Ismenian spring for water. They were slain by the spring's guardian water-dragon (compare the Lernaean Hydra), which was in turn destroyed by Cadmus, the duty of a culture hero of the new order. He was then instructed by Athena to sow the dragon's teeth in the ground, from which there sprang a race of fierce armed men, called the Spartoi ("sown"). By throwing a stone among them, Cadmus caused them to fall upon one another until only five survived, who assisted him to build the Cadmeia or citadel of Thebes, and became the founders of the noblest families of that city. The dragon had been sacred to Ares, so the god made Cadmus do penance for eight years by serving him. According to Theban tellings, it was at the expiration of this period that the gods gave him Harmonia ("harmony", literally "putting or assembling together", "good assembly", or "good composition") as wife. At Thebes, Cadmus and Harmonia began a dynasty with a son Polydorus, and four daughters, Agave, Autonoë, Ino and Semele. In rare account, the couple instead had six daughters which are called the Cadmiades: Ino, Agaue, Semele, Eurynome, Kleantho and Eurydike. At the wedding, whether celebrated at Samothrace or at Thebes, all the gods were present; Harmonia received as bridal gifts a peplos worked by Athena and a necklace made by Hephaestus. This necklace, commonly referred to as the Necklace of Harmonia,