The primitive ancestor of the Trojan line of kings is Dardanus, son of Zeus, founder and eponymus of Dardania:  in the account of later authors, Dardanus was called the son of Zeus by Electra, daughter of Atlas, and was further said to have come from Samothrace, or from Arcadia, or from Italy; but of this Homer mentions nothing.  The first Dardanian town founded by him was in a lofty position on the descent of Mount Ida; for he was not yet strong enough to establish himself on the plain.  But his son Erichthonius, by the favor of Zeus, became the wealthiest of mankind.  His flocks and herds having multiplied, he had in his pastures three thousand mares, the offspring of some of whom, by Boreas, produced horses of preternatural swiftness.  Tros, the son of Erichthonius, and the eponym of the Trojans, had three sons—­Ilus, Assaracus, and the beautiful Ganymedes, whom Zeus stole away to become his cup-bearer in Olympus, giving to his father Tros, as the price of the youth, a team of immortal horses.

From Ilus and Assaracus the Trojan and Dardanian lines diverge; the former passing from Ilus to Laomedon, Priam, and Hector; the latter from Assaracus to Capys, Anchises, and AEneas.  Ilus founded in the plain of Troy the holy city of Ilium; Assaracus and his descendants remained sovereigns of Dardania.

It was under the proud Laomedon, son of Ilus, that Poseidon and Apollo underwent, by command of Zeus, a temporary servitude; the former building the walls of the town, the latter tending the flocks and herds.  When their task was completed and the penal period had expired, they claimed the stipulated reward; but Laomedon angrily repudiated their demand, and even threatened to cut off their ears, to tie them hand and foot, and to sell them in some distant island as slaves.  He was punished for this treachery by a sea-monster, whom Poseidon sent to ravage his fields and to destroy his subjects.  Laomedon publicly offered the immortal horses given by Zeus to his father Tros, as a reward to any one who would destroy the monster.  But an oracle declared that a virgin of noble blood must be surrendered to him, and the lot fell upon Hesione, daughter of Laomedon himself.  Heracles, arriving at this critical moment, killed the monster by the aid of a fort built for him by Athene and the Trojans, so as to rescue both the exposed maiden and the people; but Laomedon, by a second act of perfidy, gave him mortal horses in place of the matchless animals which had been promised.  Thus defrauded of his due, Heracles equipped six ships, attacked and captured Troy, and killed Laomedon, giving Hesione to his friend and auxiliary Telamon, to whom she bore the celebrated archer Teucros.  A painful sense of this expedition was preserved among the inhabitants of the historical town of Ilium, who offered no worship to Heracles.

Among all the sons of Laomedon, Priam was the only one who had remonstrated against the refusal of the well-earned guerdon of Heracles; for which the hero recompensed him by placing him on the throne.  Many and distinguished were his sons and daughters, as well by his wife Hecuba, daughter of Cisseus, as by other women.  Among the sons were Hector, Paris, Deiphobus, Helenus, Troilus, Polites, Polydorus; among the daughters, Laodice, Creusa, Polyxena, and Cassandra.