So if Charlemagne's remains are exhumed and Mitochondrial DNA is collected and you can match with that sample, would you then agree that you are a descendant of Charlemagne?
Forensic geneaology has been adding samples to the Geni database. Probably a hit and a miss but worth checking by clicking the profile DNA tab and then clicking the hyperlinks for the Autosomal, Mitochondrial and Y Chromosome relatives and just see if they have put any samples there. I have found a few. Just like in the case of the Czar of Russia and his daughter Anastasia. They had several close family relatives Autosomal and Michondrial DNA Available to perform a match. Good to know stuff for somebody.