[9][10] In 13th century Brahmaputra valley the system of Baro-Bhuyan Raj (confederacy) was formed from the petty chieftains—the remaining fragments of the erstwhile Kamarupa state.
[13] The Baro-Bhuyans gradually succumbed to the Mughal dominance and eventually lost control during the reign of emperor Jahangir, under the leadership of Islam Khan I, the governor of Bengal Subah.
[18] This gave rise to the condition that individual domains were self-administered, economically self-sufficient and capable of surviving the fragmentation of central authority,[19] when the Kamarupa kingdom finally collapsed in the 12th century.
[24] As a reward, the Ahom king Suhungmung (1497–1539) settled these Bhuyans in Kalabari, Gohpur, Kalangpur and Narayanpur as tributary feudal lords.
By the mid 16th century, all the Adi Bhuyans power was crushed, and they remained satisfied with what service they could render to the Ahom state as Baruwas or Phukans, Tamulis or Pachanis.
[27] The Saru Bhuyans, who had moved west after the conflict with the Bor Baro-Bhuyans trace the genealogy of Candivara to Kanvajara, the eldest son of Sumanta, but this is not given credence.
[28] As a result of a treaty between Dharmanarayana and Durlabhnarayana of Kamata kingdom, a group of seven Kayastha (in Assam, they are commonly known as the Kalita caste) and seven Brahmin families led by Candivara was transferred to Langamaguri, a few miles north of present-day Guwahati.
Candivara chased the Bhutiyas as far as Daimara between Maguri (near Changsari town) and Dewangiri (in Bhutan), killed few of them and released his son from captivity.
[31] Candivara and his group in search of a safe haven did not stay in Lengamaguri for long and moved soon to Bordowa in present-day Nagaon district with the support of Durlabhnarayana.
During the late 14th century, Gadadhara Bar-bhuya, the younger brother of Rajadhara in order to increase his influence collected an army in Bordowa and attacked the Chutiyas and Khamtis but was held captive, he was later set free and had to settle in Makhibaha (in present-day Nalbari district).
But very soon, the rise of Biswa Singha of the Koch dynasty in Kamata destroyed their hold in Kamrup[34] and squeezed those in the Nagaon region against the Kacharis to their east.
Keeping in view the theatre of warfare between the Baro-Bhuiyans and the Mughals, the Baharistan-i-Ghaibi mentions the limits of the area bounded by the Ichamati River in the west, the Ganges in the south, the Tripura to the east; Alapsingh pargana (in present Mymensingh District) and Baniachang (in greater Sylhet) in the north.
The Baro-Bhuiyans rose to power in this region and put up resistance to the Mughals, until Islam Khan Chisti made them submit in the reign of Jahangir.