Penelope's Childhood Headcanons
(some of these are a bit dark, but they are my personal ideas, no need to agree with them)
If we put all the sources together we see that Penelope has seven brothers and one sister. We know for sure that her father is Icarius, but not all authors agree on who her mother is.
I imagine that Icarius had a first wife, the naiad Periboea (from whom were born Penelope, Perileus, Thoas, Damasippus, Imeusmius and Aletes), but that then she left the palace to return to her river and that Icarius remarried, this time with Polycaste (mother of Iftime, Aliseus and Leucadius).
But how did Icarius and Periboea meet? Icarius is wounded during a hunting trip, and runs to the river to drink. There he sees some naiads and begs them to help him, because naiads are famous for healing wounds. Periboea comes forward: she has enormous eyes, diaphanous skin and does not speak the human language. She touches Icarius' wound and he heals. Icarius falls in love with her and decides to take her with him to the palace of Sparta: he has decided that she will be the mother of his children.
But nymphs cannot stay away from their element, their source of life, for long. Periboea is stunned by dry land, walking is not natural for her, dressing is not natural, all those smells and noises are not natural. Over time she becomes more and more restless and subject to violent fits of anger. She gives birth to one child after another but when she takes them in her hands she smells only the human odor and does not understand what to do with them. Her skin begins to gray, to dry out.
One night, when Penelope is about eight years old, she is awakened by the sounds of a commotion and terrible hissing. That night Periboea runs away. The next morning Icarius seems tired, but also partly relieved. The naiad was becoming more and more difficult to handle and he was afraid that she might even hurt their children. An excuse is invented on why their mother will have to stay away for a while and the children do not ask questions. Penelope knows that she will never see her again.
She didn't have a real relationship with her mother, but she still struggles to get used to her stepmother's presence. Where Periboea was cold and silent, Policasta is sunny and talkative. She hopes she can learn to love her.
At her first menstrual cycle, Icarius decides to send her to live with his brother Tindareus. Tindareus has many daughters of her age (Timandra, Filonoe, Phoebe, Helen and Clytemnestra) and two sons (Castor and Pollux), and Penelope will be able to learn a lot from them. However, the two families had already seen each other assiduously and the cousins had always been very close. The girls go swimming together, learn the tasks of princesses and above all tell each other many secrets. Little by little they wait for the day when they will be ready for marriage.