The Kingdom of Asam now known as Ahom kingdom (/ˈɑːhɔːm/; 1228–1826) was a late medieval kingdom in the Brahmaputra Valley (present-day Assam) that retained its independence for nearly 600 years despite encountering Mughal expansion in Northeast India. Established by Sukaphaa, a Tai prince from Möng Mao (present-day Dehong Dai and Jingpo Autonomous Prefecture, China), it began as a möng in the upper reaches of the Brahmaputra based on wet rice agriculture. It expanded suddenly under Suhungmung in the 16th century and became multi-ethnic in character, casting a profound effect on the political and social life of the entire Brahmaputra valley. The kingdom became weaker with the rise of the Moamoria rebellion, and subsequently fell to repeated Burmese invasions of Assam. With the defeat of the Burmese after the First Anglo-Burmese War and the Treaty of Yandabo in 1826, control of the kingdom passed into East India Company hands.
Though it came to be called the Ahom kingdom in the colonial and subsequent times, it was largely multi-ethnic, with the ethnic Tai-Ahom people constituting less than 10% of the population toward the end.People from different ethnic groups became a part of the Ahom population due to the process known as Ahomisation. The identity of the Ahom people in this kingdom was fluid, with the king controlling who belonged to it and who did not. The Ahoms initially called their kingdom Mong Dun Shun Kham till 1401 (Assamese: xunor-xophura; English: casket of gold), but adopted Assam in later times. The British-controlled province after 1838 and later the Indian state of Assam came to be known by this name. The kingdom maintained close political ties with other Tai-states especially with Mong Kwang (Nara) till the end of its rule in the 19th century.