Helen and Penelope: A doublet? But why?

Reading Homer closely reveals a problem: what exactly has happened to Helen and Penelope. The two share strong parallels: Helen’s marriage to Menelaos was preceded by being courted by an army of suitors; Penelope too was courted by an enormous group of suitors.

Helen is stolen away by Paris and needed to be won back by her proper husband. Only a slight change has been made in the case of Penelope, namely that Odysseus’ return prevented the stealing away.

Other passages too suggest a doublet: The most telling is, where Helen recalls the incident of Odysseus sneaking into Troy, how she recognised him immediately but chose not to betray him. The question may arise how she knew how Odysseus looked like. When or where could she have met him before?

In this passage we find explicitly stated that Odysseus entered the city disguised as a beggar; that Helen alone saw through his disguise; that he cleverly evaded her questions; that she made arrangements for a bath for her disguised guest; that she swore not to reveal him to his enemies; and that afterwards there was lamentation among the other women at what had happened.

These events are clearly identical to those in the Odyssey: the late-night conversation between Penelope and Odysseus. Penelope likewise was the first to recognise Odysseus.

The question should be: is the character of Helen a doublet of Penelope, or vice versa. There can be no doubt that Helen is the original. Without Helen, the entire basis for the historical Trojan War, and the reason for Odysseus being absent in the first place, would be gone.

But what prompted Homer to use a character twice? Was Penelope perhaps a figure already established in myth in a different context?

She may have been borrowed from an Arcadian cult: Penelope was worshipped in Mantineia as the mother of Pan. Later, after the Homeric epics were famous throughout the Mediterranean region, worshippers changed the role of Penelope and she became Odysseus' wife. After Odysseus found that she had committed adultery and expelled her from his house, she came to Arcadia and there gave birth to Pan.

Odysseus’ household contained no one for him to return to. The original story, therefore, was not about Odysseus’ return but rather about an invasion, about a foreigner arriving and attacking the local defensive force, the 'suitors', killing them, and claiming the throne.

This explains problems in the conflict between Odysseus and the 'suitors'. In the Odyssey, the suitors are guests under the protection of Zeus, and killing them would have been viewed as a crime against Zeus. In the original form of the tale, however, they enjoyed no such protection, and so Odysseus could attack and kill them without any divine repercussions.

Given the strong ties that Odysseus has with northwestern Greece, the original form of the 'return' story likely was about an invasion from the northwest.

Source.