Belyak was a fief or administrative subdivision in Medieval Volga Finnic states. [1] [2]
The same as beylik , [3] equivalent of county in other parts of Europe. [4]
Temnikov Principality and Mordvin Horde were divided into belyaks. After Russian Colonization they transformed into uyezds, [5] modern day raions and aimaks in Mordovia.