I'd agree with the overlap thought. You could possibly say the medieval era spanned roughly from 500 to 1500. It would be difficult to set an exact date due to local differences like urbanization rate etc. You can, of course, choose an exact date to the beginning of the renaissance in italy, but does that count for some eastern pomeranian peasant village?

Brutus, are differences in french and german feudalism important to the matter at hand? It is, no matter which degree of access the respective king had to his vassals, both feudalism.