WHAT HAPPENED IN 1236 ad.

Led by Batu Khan, Mongol forces numbering more than 300,000 soldiers struck again in 1236.[3] They besieged and seized Bilär, Bolghar, Suar, Cükätaw, and other cities and castles of Volga Bulgaria. The inhabitants were killed or sold into slavery. Volga Bulgaria became a part of the Ulus Jochi, later known as the Golden Horde. The territory was divided into duchies; later each of them received some autonomy as vassal states of the Golden Horde.