The Telegony was a short 2-book epic poem recounting the life and death of Odysseus after the events of the Odyssey. In this mythological postscript, Odysseus is accidentally killed by Telegonus, his unknown son by the goddess Circe. After Odysseus' death Telemachus returns to Aeaea with Telegonus and Penelope, and there marries Circe.
From the Dictionary of Greek and Roman Biography and Mythology:
The son of Odysseus and Penelope (Hom. Od. i. 216). He was still an infant at the time when his father went to Troy, and in his absence of nearly twenty years he grew up to manhood. After the gods in council had determined that Odysseus should return home from the island of Ogygia, Athena, assuming the appearance of Mentes, king of the Taphians, went to Ithaca, and advised Telemachus to eject the troublesome suitors of his mother from his house, and to go to Pylos and Sparta, to gather information concerning his father. Telemachus followed the advice, but the suitors refused to quit his house; and Athena, in the form of Mentes, accompanied Telemachus to Pylos. There they were hospitably received by Nestor, who also sent his own son to conduct Telemachus to Sparta. Menelaus again kindly received him, and communicated to him the prophecy of Proteus concerning Odysseus (Hom. Od. i.–iv.). From Sparta Telemachus returned home; and on his arrival there, he found his father, with the swineherd Eumaeus. But as Athena had metamorphosed him into a beggar, Telemachus did not recognise his father until the latter disclosed to him who he was. Father and son now agreed to punish the suitors; and when they were slain or dispersed, Telemachus accompanied his father to the aged Laertes. (Hom. Od. xv.–xxiv.; comp. Odysseus.) In the Post-Homeric traditions, we read that Palamedes, when endeavouring to persuade Odysseus to join the Greeks against Troy, and the latter feigned idiocy, placed the infant Telemachus before the plough with which Odysseus was ploughing (Hygin. Fab. 95; Serv. ad Aen. ii. 81; Tzetz. ad Lycoph. 384; Aelian, V. H. xiii. 12.). According to some accounts, Telemachus became the father of Perseptolis either by Polycaste, the daughter of Nestor, or by Nausicaa, the daughter of Alcinous (Eustath. ad Hom. p. 1796; Dict. Cret. vi. 6.). Others relate that he was induced by Athena to marry Circe, and became by her the father of Latinus (Hygin. Fab. 127; comp. TELEGONUS), or that he married Cassiphone, a daughter of Circe, but in a quarrel with his mother-in-law he slew her, for which in his turn he was killed by Cassiphone (Tzetz. ad Lycoph. 808.). He is also said to have had a daughter called Roma, who married Aeneas (Serv. ad Aen. i. 273.). One account states that Odysseus, in consequence of a prophecy that his son was dangerous to him, sent him away from Ithaca. Servius (ad Aen. x. 167) makes Telemachus the founder of the town of Clusium in Etruria.
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