Helen and Penelope, the two most important women of Homeric epic, appear to be cousins! How can this be the case? Their fathers, as one might imagine, were brothers (Apollodorus 3.126):
“There are some who say that Aphareus and Leukippos were sons of Periêrês the son of Aiolos and that Periêrês was the son of Kunortos, but that he himself was the father of Oibalos who fathered Tyndareus, Hippokoôn, and Ikarios.
Hippokoôn had for children Dorykleus, Skaios, Enarophoros, Euteikhes, Boukolos, Lukaithos, Tebros, Hippothoos, Eurytos, Hippokorustês, Alkinoos,and Alkôn. With these sons, Hippokoôn expelled his brothers Ikarios and Tyndareus from Lakedaimôn. The pair fled to Thestios and they allied with him in the war against his neighbors. So, Tyndareus wed Thestios’ daughter, Lêda. And then, when Herakles killed Hippokoôn and his sons, they returned, and Herakles handed over the kingdom of Tyndareus.”
εἰσὶ δὲ οἱ λέγοντες ᾿Αφαρέα μὲν καὶ Λεύκιππον ἐκ Περιήρους γενέσθαι τοῦ Αἰόλου, Κυνόρτου δὲ Περιήρην, τοῦ δὲ Οἴβαλον, Οἰβάλου δὲ καὶ νηίδος νύμφης
Βατείας Τυνδάρεων ῾Ιπποκόωντα ᾿Ικάριον.
῾Ιπποκόωντος μὲν οὖν ἐγένοντο παῖδες Δορυκλεὺς Σκαῖος ᾿Εναροφόρος Εὐτείχης Βουκόλος Λύκαιθος Τέβρος ῾Ιππόθοος Εὔρυτος ῾Ιπποκορυστὴς ᾿Αλκίνους ῎Αλκων. τούτους ῾Ιπποκόων ἔχων παῖδας ᾿Ικάριον καὶ Τυνδάρεων ἐξέβαλε Λακεδαίμονος. οἱ δὲ φεύγουσι πρὸς Θέστιον, καὶ συμμαχοῦσιν αὐτῷ πρὸς τοὺς ὁμόρους πόλεμον ἔχοντι· καὶ γαμεῖ Τυνδάρεως Θεστίου θυγατέρα Λήδαν. αὖθις δέ, ὅτε ῾Ηρακλῆς ῾Ιπποκόωντα καὶ τοὺς τούτου παῖδας ἀπέκτεινε, κατέρχονται, καὶ παραλαμβάνει Τυνδάρεως τὴν βασιλείαν.
The story according to a Homeric scholiast is presents even more family dysfunction (Schol. b in Il.2.581-6):
“Oibalos, the son of Perierês, ruled the Lakadaimonians and his children were Tyndareus, Ikarios, Arênê and the bastard Hippokoôn who conspired with Ikarios and drove Tyndareus away. He was ruling with his many sons.”
Οἴβαλος ὁ Περιήρους ἦρχε Λακεδαιμονίων, οὗ Τυνδάρεως ᾿Ικάριος ᾿Αρήνη καὶ νόθος ῾Ιπποκόων, ὃς συμφρασάμενος ᾿Ικαρίῳ τὸν Τυνδάρεων ἀπελαύνει, καὶ ἄρχει πολλοῖς πλήθων υἱοῖς.
According to the rest of this tale, Herakles came and killed Hippokoôn and his sons after he sacked Pylos. Menelaos was only in charge of the contingent, according to the scholiast, because Helen’s brothers were not there.
Some of these details are confirmed by a scholiast writing on Euripides, Schol. In Euripides Orestes 457
“These are the children of Oibalos,the son of Periêrês: Tyndareus, Ikarios, Arênê, and Hippokoôn, a bastard from Nikostratê. After the death of Oibalos, the children struggled over who would rule. Ikarios made a pact with Hippokoôn and drove Tyndareus out of Sparta. Tyndareus lived afterwards in the farthest reaches of Lakedaimonia and married Leda, the daughter of Thestios the Aitolian.
She gave birth to Kastor and Polydeukes, Timandra, Klytemnestra, and Helen. Later, Herakles killed Hippokoôn and his sons in exchange for the murder of Oiônos; then he returned Tyndareus from Phrixê and Pellênê and entrusted the rule of Sparta to him. For Herakles married Leda’s niece, Deineira.”
Οἰβάλου τοῦ Περιήρους παῖδες οὗτοι· Τυνδάρεως, ᾿Ικάριος, ᾿Αρήνη, καὶ νόθος ἐκ Νικοστράτης ῾Ιπποχόων. οὗτοι μετὰ θάνατον Οἰβάλου ἐστασίασαν περὶ τῆς ἀρχῆς. ᾿Ικάριος δὲ συνθέμενος μετὰ ῾Ιπποκόωντος ἐξελαύνει τὸν Τυνδάρεων τῆς Σπάρτης.
ὁ δὲ οἰκεῖ ἐν τοῖς ἐσχάτοις τῆς Λακεδαιμονίας καὶ γαμεῖ Λήδαν τὴν Θεστίου τοῦ Αἰτωλοῦ, ἐξ ἧς ἔσχε Κάστορα καὶ Πολυδεύκην καὶ Τιμάνδραν καὶ Κλυταιμνήστραν καὶ ῾Ελένην. ὕστερον δὲ ῾Ηρακλῆς ἐπὶ τῷ φόνῳ τοῦ Οἰωνοῦ φονεύσας ῾Ιπποκόωντα ἅμα τοῖς παισὶ καὶ καταγαγὼν τὸν Τυνδάρεων ἀπὸ Φρίξης καὶ Πελλήνης ἐγχειρεῖ αὐτῷ τὴν ἀρχὴν τῆς Σπάρτης. ἐγάμει γὰρ ῾Ηρακλῆς Δηϊάνειραν τὴν Λήδας ἀδελφιδῆν: —
[Leda is not universally a daughter of Thestios. Thestios’ other daughter was Althaia, who married Oineus and gave birth to Meleager and Deineira. According to another tradition, attributed to Eumelos of Corinth, Leda was the daughter of Glaukos and Panteiduia. And let’s not even bring Pherecydes into this. Because, well, there are even more accounts to consider…]