I was able to prove my lineage to Charlemagne in 2019 with Membership in the Order of the Crown of Charlemagne through my Spanish Royal Gateway Ancestor Juan Montes Vigil. This was accomplished with Birth, Marriage, death records as well as wills.
Usually the problem in real Genealogy is finding a creditable proven & accepted Gateway Ancestor, as most ancestry errors are made at this transition point.
My Ancestor Juan Montes Vigil, was the first Spanish Royal Gateway Ancestor to be accepted by North American lineage Societies as an acceptable Royal Gateway Ancestor for Membership.
In my Wiki tee I still have to add 6 Profiles to connect, FERNANDO PÉREZ PONCE DE LEÓN, (WikiTree ID: De_Leon-296) with my Maria de Quiros y Miranda (WikiTree ID: De_Quiros_y_Miranda-1) to match my Approved OCC membership Application.
I have been unable to add the 6 profiles because of the Pre-1500 tag needed to add the profiles.
To check to see if you have a Gateway Ancestor that will be acceptable beyond any doubt, just look at the Gateway Ancestor list at:
https://www.charlemagne.org/Gateway.html
If your Gateway Ancestor is not on that list, you would have to prove the whole line with period sources, once that has been done their names is added to the list as a proven Gateway.