In the same way poems and even romances were repeated, as in Homer's day or in the time of the Norse sagas, by word of mouth.

None of their secret knowledge was written down.

Like the ritual of Freemasonry it was considered too sacred.
Moreover, when men lived for hundreds of years this was not so necessary, especially as their great fear was lest it should fall into the hands of the outside nations, whom they called Barbarians.

For, be it remembered, these Sons of Wisdom were always a very small people who ruled by the weight of their intelligence and the strength of their accumulated lore.

Indeed, they could scarcely be called a people; rather were they a few families, all of them more or less connected with the original ruling Dynasty which considered itself half divine.