[quote=@Vahir]
Khazaria surviving would have wide-ranging effects on Eastern Europe. Primary among which, I think, is that the Russian principalities would have been shielded from the mongol steamroller. The way I see it, this would have two effects:

1. The Russians wouldn't be weakened enough for the Lithuanians to grab all their land, so your Hungary-Poland might exclude things like Galicia.

2. On the other hand, the Russians would never have a reason to unite, so they'd probably be shattered into little principalities anyway.  
[/quote]

Also, im planing on having the Khazar's conversion to Judaism be much more agressive, that being them enforcing conversion on the peasents and conquered people (aka the Kievan Rus and other East Slavs). This would give them a better sense of unity and identity, plus im wondering how the presence of a massive Jewish majority state would effect Eastern Europe as well