The Hobbit - Chapter 18 - The Return Journey

[davem]

Originally Posted by Bêthberry

As for Michael's fears of spiders, Tolkien and Christopher shared dreams of sunken civilisations. That does not make Numenor childish.

Numenor was part of the 'adult' mythology. TH was (originally) not. I suspect Tolkien was both using his knowledge of ancient myth as inspiration & attempting to inspire a love of it in his children by presenting them with the 'Archetypes' behind their loved objects. Of course, he was also, by bringing in aspects of his Legendarium in the stories he wrote for them, introducing them to that too. He does a similar thing by his use of implied back-story:

Gandalf came by. Gandalf! If you had heard only a quarter of what I have heard about him, and I have only heard very little of all there is to hear, you would be prepared for any sort of remarkable tale. Tales and adventures sprouted up all over the place wherever he went, in the most extraordinary fashion.

Any child reading or hearing this would be begging for more stories about Gandalf. One can assume that references to Gondolin, runes, etc, would have the same effect.