Creative Commons License
A Creative Commons (CC) license is one of several public copyright licenses that enable the free distribution of an otherwise copyrighted work. A CC license is used when an author wants to give people the right to share, use, and build upon a work that they have created.
https://en.wikipedia.org/wiki/Creative_Commons_license
This would leave anybody the right to view it, use it, etc as long as its attributed. The King's still get attribution, but won't profit from it, which seems to be the crux of the reason they don't do it. Sad really.