According to the local traditions, the Rengmas and the
Lothas (or Lhotas) were once part of a single
ethnic group. There are also oral records of a mighty struggle between the combined Rengma villages and the Lotha village of Phiro. There are records of the Rengmas' conflict with the
Angami Nagas.
Slavery used to be a practice among the Rengmas, and the slaves were known by the names
menugetenyu and
itsakesa. By the time the British arrived in the Naga region, slavery was a declining practice, and no Rengma appears to have been a slave during this time. In Assam, the Rengma people are found in the
Karbi-Anglong, the then Mikir Hills. The Rengmas migrated to the then Mikir Hills in the early part of the 1800s. The migration of the Rengmas can be traced in the books written by JP Mills, ICS on the following: In the book 'Travels in Assam' written by John Butler, specifically mentioned on page number 126 that beyond the Kuleanee river, the Rengmah (sic) boundary commences and terminates with the Dhunseeree (sic) river, separating Now-Gong from the Seebsaghur (sic) district. John Butler writes in 'Traves in Assam' on page number 121 that in 1839, Mr. Grange, Sub-Assistant Commissioner, seems to have been the first European officer who met the Rengma Naga in the vicinity of Mohung Dehooa, on his way to the Angami Hills. Butler opines that no revenue settlement was ever made or written agreement taken from them to pay the revenue, till February 1847. Mr. Sub-Assistant was deputed in December 1847 to enter the
Rengma hills from Golaghat; but after visiting many villages, he found the country so heavy and impassable from the dense wet jungles and was forced to return to the plains at Kageerunga (sic). He again met the Rengma Naga and the first revenue settlement with the Rengma Naga villages, discovered thirty-two in number and was successfully paid. "The Rengma Nagas" written by JP Mills, MA, Indian Civil Service, Honorary Director of Ethnography Assam in 1936 in Introductory part in page 2 states, "About a hundred years ago or more a body of the western Rengmas migrated north-west to the Mikir Hills, where they are still living." () The book "The Lhota Nagas" written by JP Mills, ICS in 1922 in page xiv of the Introduction states, "Indeed it is now no longer quite clear whether this chief was a Lhota our a Rengma, and whether he protected against the pursuing Angamis the rearguard of the Lhotas crossing the Dayang northwards, or that of the Rengmas migrating westwards to the Mikir Hills....." Page xix of the same book states, "The Rengmas thus migrated from the Kezami-Angami country, throwing out the Naked Rengmas eastwards to Melomi, and ultimately sending the bigger portion of the tribe westwards to the Mikir Hills." () The Rengmas claim that they are native or aborigines of Karbi-Anglong. Karbi oral history claims that they immigrated from the
Yunnan region of China in ancient times. The Rengmas have come under pressure from militant factions, a hidden policy adopted by people between various
ethnic groups interest and unity, and have retaliated by forming their own counter-militancy groupings, leading to ethnic killings and polarization in Karbi-Anglong, and the plight of both Karbis and Rengmas to relief camps. Parallel to the Rengmas, the Kukis, who have an anti-Naga tendency in the last few decades, also have militant groups active in Karbi-Anglong fighting for the rights of their
ethnic group. ==Subgroups==