Yep, crusade. Greece is now a Frankish/Greek/Persian/Arab amalgam while Byzantium tries to assimilize the last Slavs not under my rule.I'm more interested in the Knights Templar replacing Byzantium. I don't even know how this is possible since Knights Templar can only castles in Catholic provinces, whereas the Greeks are Orthodox. And they're only given castles, not whole counties and duchies.
Edit: Ah. Byzantium must have lost it in a Jihad, and then the Knights regained it in a Crusade.
Holy orders often win crusades these days - so I found the Celtic-Castilian Wars more interesting.