As mentioned already, it's not going to work if Islam and Christianity arise. We need either a failure of absolutist monotheism ("those who won't join us are against us, and eternally damned to boot!") [1] to arise or the Roman Empire converting to Judaism. Or perhaps an early collapse of the Roman Empire that allows the Jews to establish themselves as a regional power, although long-term survival is trickier, especially if the aformentioned monotheism arises. In any event, things must change sufficiently that you are not going to get anything at all like our 1096.
Bruce
[1] Israel probably still gets conquered a few times, being where it is, but other states - Armenia, Georgia - have been conquered to reemerge later.