One thing I've begun to wonder about while playing Crusader Kings 2: would it have been possible for an independent state to be established somewhere in Europe or the Middle East in the medieval era that was led by a Jewish dynasty of some sort (and could have survived for at least a few decades, but preferably more)? Specifically, I was thinking of any such possibilities after the fall of the Khazar Khaganate (which, IIRC, had a Judaic ruling dynasty during at least some of its existence). The one requirement is that it would have to be ruled by explicitly Jewish kings, not secret adherents of Judaism outwardly professing a more mainstream religion (doesn't necessarily have to be 'Israel' as such, however). I already know about Beta Israel, but I was thinking of something closer to Europe... I realize this is kind of a long shot given how scattered the Jewish diaspora was at the time, but could one Jewish group or another have seized power in a chunk of territory close to the Christian or Muslim heartland and established a kingdom of its own there?