Why did King Kilydd conceal his son from his wife?

Question

In Culhwch and Olwen, King Kilydd's wife, Goleuddydd, dies in childbirth, leaving behind the king's only son. She tells him to go forth and remarry once two briar blossoms bloom on her grave, and he does so when the blossoms appear seven years later.

He finds a maiden to marry, kills her husband (another king), and plans to marry her. Then something curious happens (dramatic emphasis mine).

On a certain day, as the lady walked abroad, she came to the house of an old crone that dwelt in the town, and that had no tooth in her head. And the queen said to her, "Old woman, tell me that which I shall ask thee, for the love of Heaven. Where are the children of the man who has carried me away by violence?"

Said the crone, "He has not children."

Said the queen, "Woe is me, that I should have come to one who is childless!"

Then said the hag, "Thou needest not lament on account of that, for there is a prediction that he shall have an heir by thee, and by none other. Moreover, be not sorrowful, for he has one son."

The lady returned home with joy; and she asked her consort, "Wherefore hast thou concealed thy children from me?"

The king said, "I will do so no longer." And he sent messengers for his son, and he was brought to the Court.

I'm somewhat confused by the fact that the crone at first says that Kilydd has no children, then tells his new wife the truth. Even more puzzling, though, is that the king concealed his son.

My question is the same as the unnamed wife's: Why did Kilydd hide his son from her?

Answer 1

King Kylydd did the right thing in concealing his son from his new wife, because once she sees Kilhwch (Culhwch), she places a curse on him:

His stepmother said unto him, "It were well for thee to have a wife, and I have a daughter who is sought of every man of renown in the world."

"I am not yet of an age to wed," answered the youth. Then she said unto him, "I declare to thee, that it is thy destiny not to be suited with a wife until thou obtain Olwen, the daughter of Yspaddaden Penkawr."

This is easy to miss, because the characters act like it's no big deal: Kilhwch is told that it "will be easy for thee" to marry Olwen. However, keep in mind the following three things:

1. It wasn't easy: the characters have to achieve several supposedly impossible magical tasks in order for Kilhwch to be able to marry Olwen.
2. These characters are accustomed to magic (the relationship between the real world and the magical world is a common theme in the Mabinogion).

3. A central theme in the story is the control of reproductive power. This story features a "jealous stepmother" motif; to quote from Will Parker's Mabinogion.info (which quotes Stephen Knight's Culhwch analysis):

   The threat represented in the essential plot of the story us the failure of the family to reproduce itself. The stepmother’s curse means Culhwch will either go childless or be killed by the giant … the central fear [is] of a sterile generation and of reproductive power lying in enemy hands, whether giants or stepmothers. (Arthurian Literature and Society Macmillan Press, 1963 pp 16-18)

   The story is, in a way, a precursor to stories like Cinderella: the stepmother wants to control the father, so she controls the father's children with his first wife.

I don't know why the crone first concealed Kilhwch (Culhwch) from the stepmother, and then revealed Kilhwch to her. That could be explained as an inconsistency in the text, or as the stepmother persuading the crone with her emotion by her "lament on account of that."

(The stepmother said "woe is me, that I should have come to one who is childless!" when she heard King Kilydd had no children. This is another example of the importance of fertility: she wants to be able to have children and control the King.)

Answer 2

The stepmother is a metaphor for death. She comes forth (Via Magic) to remind King Arthur of his wife Guinevere and is there to torment him.

The crone is Mordred, and she is seeking revenge on the King for banishing her to the wilderness and her eventual fall in the Battle of Camlann.

The child is Lohot, who grows to be great knight and traveler, although he had a falling out with his father Arthur, so chose to leave Camelot and seek his fortune elsewhere. He was considered beautiful by all who laid eyes on him and had a large following of knights and maidens.

The Step mother is also smitten with Lohot so steals away in the night with her trusted aide Kay. She is eventually bedded by Lohot and dies giving birth to their daughter Lisanor.