OOC: Pretty sure it is ridiculously unlikely that the Chinese and Indian communities will be gone by 11th Century. There is very little reason for local communities to become so hostile in that timeframe, without another Abrahamic faith providing the impetus.
IC: Maybe you'd need the Roman-Sassanian War of 602-626 to go the other way. Persians were doing alright till they had to face Heraclius, who basically smashed all the Persian armies in Mesopotamia, integrated it into the Empire and then went on a bloody purge against Jews since some had apparently helped Persians sneak into Palestine and sack Aelia Capitolina (OOC: Jerusalem). Heraclius's policies definitely shaped the way the rest of Christendom treated Jewish people (even in places as newly converted as Khazaria), so just getting rid of him/his dynasty (or making them less successful in restoring control over the Med) would help a lot. Apparently some Emperor in the 9th Century went as far as to ban the religion itself and the law is still in the code within the Empire, which is funny as I have definitely met Reconstructionists in Alexandria and Constantinople and they did not seem to be aware of that.... Hope they don't run into trouble with the law, since I can see some vindictive fundie being willing to use that.