History about an non European culture during the middle ages

Hello everybody I have a problem for history I have to do an group work about a non European culture during the middle ages so since the there was a limited choice.And the Byzantines are the only non western culture i care about i picked the Byzantines however i am really good at history but byzantine bureaucracy is one of the few area's in history where i don't know much about so and can't seem to find much info about so i hoped that i could find help form fellow interested,history freaks,historians like me (BTW sorry for the spelling faults).

Byzantines is kind of a crossover between European and Eastern I think... If you want to do an assignment of an not-European civilization during our middle-ages you should probably go with Inka, Chinese, Japanese or even Mongol instead... Otherwise you could choose the ottoman empire, sure it`s in the late middle-age but still... then you could include byzantine culture and the empire when they clashed. 
The Byzantines were Europeans, they called themselves "Romans", because they were the descendants of the Eastern Roman Empire. They were Christians and their language was Greek as well. The sassanids are bad choice too, because their state was a Late Antique empire (224-651). I think antiquity lasted for the Muslim conquest in that area. The khazars' empire was Eastern-European as well. If I were you, I would choose the Mongols (Genghis khan's empire).