Koch Dynasty
See: Koch dynasty
The Kamata kingdom then passed into the hands of another Tibeto-Burman group, the Koch Rajbongshi, giving rise to the Koch dynasty. In the 16th century itself, one of the princes then ruling the eastern portion of the kingdom (Koch Hajo) declared independence, and the two parts remained separated for ever, the boundary between the two forming roughly the boundary between the present Assam and West Bengal.
The Koch Hajo kingdom soon came under attack from the Mughal, and the region went back and forth for a number of times between the Mughal and the Ahoms, and finally settling with the Ahoms. The western portion (Koch Bihar) first befriended the Mughals and then the British, and the rulers maintained the princely state till the end of the British rule.
Read more about this topic: Kamata Kingdom