Cheers,
CSG
These things are actually part of an older tradition - as you say in fact. I mentioned printing because that was the first indication of the demand for these things.
Ariosto was certainly not the first such fantasist. "Orlando" is actually a sequel to Boiardo's similar work (I assume, since I have not read Boiardo).
I have no problem with calling "Orlando" a work of the Renaissance. The 1500 cutoff is pretty arbitrary.
My larger point is that Potter and its ilk have ancient roots, and sure, they are not necessarily Christian ones. But even Christianity did not lack such influences, from St. Paul onwards.