Before the invasion of Ahom headed by Sukhapha in 1228 A.D. the country was ruled by the various Bodo rulers throughout the length and breadth of the kingdom of Kumar Burman in the seventh century i.e. "Kamrup", whose land was about 10,000 (roughly 1,700 miles) in circuit, and also which was pointed out by Sir Edward Gait in his "A History of Assam", that a kingdom of this size would encompass the whole of Assam (except the Naga Hills, the Mizo Hills and Manipur) as well as Bhutan and part of North Bengal." This may be compared with that of a valuable statement made by Dr.S.K.Chatterjee in his book 'Kirata-Jana-Kirti', "The Bodos, who spread over the whole of the Brahmaputra Vally and North Bengal as well as East Bengal, forming a solid block in North Eastern India, and they form one of the main basis of the present day population of these tracts."
  
The Kamata kingdom near Cooch Behar which was attacked and overtaken by Hussein Shah, the then ruler of Gaur (Bengal) towards the end of the 15th century probably in 1498 A.D. did not last long. Because, a Bodo chief Viswa Singha by name became prominent in Chiking in 1515 A.D. who later shifted his capital to Cooch Behar.
  
Many series of Bodo kings enjoyed their sovereignty in this extreme western part of the Bodo kingdom within the medieval era of the Indian history which extended upto Lakhimpur and the last king of which the royal dynasty was Indira Narayan (11682-1725 A.D.)
  
This western part of the Bodo kingdom had a close connection of the Duars (12 Duars) and the Dewangiri areas were concerned and the latter it was transferred to Bhutan by an agreement made in between the king of Bhutan and the first Prime Minister of India (after independence) Late Pandit Jawaharlal Nehru in 1949.
  
The Bodo kings (who have been shown as the Koch kings by the Hindu writers) had embraced Hindu religion and gradually they did abandon their ancestral Bodo language which certainly brought the present darkness and obscurity in these lines of kings-but the majority of the Bodos are still continuing to be as Mongolian Bodos, preserving their language, culture and their distinct mode of Mongolian civilization whereas the bulk of the Hinduised Bodo are now known as the Rajbangsis who have been classes as other backward class (OBC) now in state of Assam.
  
In the Surma Valley i.e. in the Cachar kingdom, the Bodo kings (who have been shown as the Kachari kings) maintained their Sovereignty upto 1854 A.D. when the last king Tularam Senapati died childless and the country was annexed with Nowgong district by the British applying the doctrine of lapse. Tularam Senapati revolted against the king Krishna, the Mongolian 'Bathou' religion and his sovereignty was recognized by the British in 1830 when Gobinda chandra (Iragdao) died childless.
  

The Aham kingdom was founded by Sukhapha in 1228 A.D. after conquering the lands of the Bodos who ruled in the Upper Assam under the titles, Moran,Borahi and Chutiya (may be chieftains) as called by the Hindus respectively. Afterwards the Ahom attacked Dimapur in 1488A.D. the capital of the Bodo Empire. Later, the capital was shifted to Maibang in 1536 A.D. and then to Khaspur in the Plains of Cachar and Cacharis enjoyed their sovereignty till the death of the last king Tularam Senapati in 1854 A.D.
On the other hand, the Ahom kings ruled upto 1838 A.D. by the last king Purandar Singh in Upper Assam (1832-1838) and after which the date the Ahom kingdom came completely under suzerainty of the British Empire through the East India Company.
  
From this record it reveals that the Bodos are the latest power to lose their kingdom in comparision to Ahom in Assam and the origin of words 'Assam' and Assamese were the 'Ha-sham' and 'Ha-sham-sas' meaning the land of the Shams, i.e. Tai people and sons of the 'Ha-shams' respectively and still the Dimasa Bodo of the North Cachar Hills call the Assamese people as 'Ha-sham-sas', Assam and Assamese are anglicized from of those Bodo words 'Ha-sham' and 'Ha-sham-sas'.
  
Now let us have a glance over 'Tripura' which the Bodo state was once amalgamated with the East Bengal by Britishers.
To bring it into light, it will be sufficient to quote some from the pen of Mr. V.J.K.Sarin's 'North-East India in Flames' who stated as, 'The name Tripura is evidently a Sankaskritised adaptation of the early Bodo name (Tripura) by which the tribe was known.'
'The Tripuries, as is now well-known fall under the Bodo group of Indo Mongoloids.
  
All other tribes from the Garos can be categorized up to Tripura belongs to this group, while the Garos can be categorized as the Western Bodos, the Tripuries are known as the southern Bodos'.
  
'King Ratna Manikya ruled Tripura during the later part of the 13th Century and he is believed to have settled about ten thousand Bengalis belonging to various professions in his kingdom and thus led to the closer affroximation of both the royal family and rank and file of the Indo-Mongoloid people of Tripura State to Bengalis, in religion and culture; and it meant also the establishment of Bengali and Sanskrit as cultural and religious languages of the Tipra people (Kirata-Jana-Kriti).
  
It was during the reign of Dharma Manikya in the 15th century that this process of conversion to Hinduism assumed greater significance and become more meaningful. Dharma Manikya was a devote Hindu. It was he, who for the first time made Bengali Official and court language of Tripura. With the advent of Hinduism the traditional religion of the tribal people did not, however, disappear. Although, relegated to a secondary position, many a pure Hindu ritual is still in vogue amongst the Tripuries, so much so that it is still retain a good deal of their medieval political and cultural milieu, although Hinduaisation had mad strides among them.'
  
Tripura is tiny state with an area 10,447 sq.kms. It was a princely state in time of the amalgamation with east Bengal and the Bodo Maharaja of Tripura enjoyed suzerainty on his own state. In early period of the name of this state was 'Tripura' after the Bodo word 'Tipra' meaning a flat, short, small in size. It meant that the Bodo king who ruled in the part of the Bodo kingdom was small in size, so the name this state was known as Tipra - Tripura, after his name. Sir Edward Gait mentioned that the king of hill Tippherah gave the whole of Surma Valley as a dowry while giving his daughter in marriage to the king of Maibong. The present Tripura being recorded as Tripura in the Linguistic Survey of India-Vol.I No.III-part-II. In the map while showing the areas inhabited by the Bodo group of people by G.A.Grierson in 1930. But it is made Tripura, a Sanskritised name.
  
What does it mean now by Tripura? In Hemkosho Dictionary it is given as follows :- "Tripura name of a demon, Tripura name of Goddess, name of a district in east Bengal." But what is happening in this 'Tribal-Bodo State' of Tripura now (?) and one will get discouraging answer-'Tripura's populations complex is very different from that of any other tribal state in the North-East. The tribals here are vastly out numbered by the Bengali immigrants from the neighboring Sylhet, Commilla, Noakhali and Chittagong districts of East Bengal, now Bangladesh. Tripura, therefore, could not be listed as a tribal state proper in the constitution, although its original inhabitants were the Tripuris, the Reangs, Jamatias, Chakmas, Halams and 14 other hill communities.'