Mostly a good comment but, for one from what I've heard there's nothing to suggest the force fought at Tours wasn't just a raiding party.Only in 732 the Franks stopped the muslim world conquest attempt by crushing them at Tours.
(as it's likely the muslims would have erased most evidence).
Also not sure where you're going with the assertion Muslims would erase the memory of Christianity. We know about Ba'al, and Moloch, and Gilgamesh do we not? About Ahura Mazda? Zoroastrianism was in a position of strength close to Christianity when the Arab invasions started, but people still remember Zoroastrianism and still worship Ahura Mazda.