Islam only dates back to 610 with one person. So, I am not sure how 'Islamic' the area was around 900-1000.
After all, Christianity to a long time to become central in Europe. In 300 they where only something like 10% of the Roman population. Not to mention looking very different from 'Modern' Christianity.
https://en.wikipedia.org/wiki/Science_in_the_medieval_Islami...