> Christian monastery in Islamic Sinai if the timing of the article is correct

https://en.wikipedia.org/wiki/The_Ladder_of_Divine_Ascent

According to this article his writings pre-date the Islamic conquest (639).

Of course, there was also this: https://www.sinaimonastery.com/index.php/en/history/mohammed

And St Catherine's is a fortress in the middle of the desert so who knows what it's status was, it was an interesting time (beginning of Islamic conquests).