Adolf Hitler famously admired Islam and wished the Germanic people's had converted to it instead of Christianity.
"Hitler said that the conquering Arabs, because of their racial inferiority, would in the long run have been unable to contend with the harsher climate of the country. They could not have kept down the more vigorous natives, so that ultimately not Arabs but Islamized Germans could have stood at the head of this Mohammedan Empire."
This quote is from Albert Speer.
Basically what if after an Islamic victory at Tours the Germanic tribes become Islamized and then go to rule the Muslim world or large parts of it by the 10th century AD.
Is this possible? Could the islamized Germans in such a world have ascended to such heights?