"So then, using the same logic, and since France did not come into existence until 843, Charles Martel is not French"
You meant 1843, of course. I agree, Martel was not French.
And Roger Staubach was not a Dallas Cowboy when he played for Navy, even though the Cowboys did exist at the time.
"In the 4th century AD, Gaul's eastern frontier along the Rhine was overrun by Germanic tribes, principally the Franks, from whom the ancient name of "Francie" was derived. The modern name "France" derives from the name of the feudal domain of the Capetian Kings of France around Paris. Existence as a separate entity began with the Treaty of Verdun (843), with the division of Charlemagne's Carolingian empire into East Francia, Middle Francia and Western Francia. Western Francia approximated the area occupied by modern France." -- Source
P.S. Never, EVER talk about the Cowboys when discussing anything French...including French wine, French toast, or even French ticklers.