"a process of Aryanisation in which even some tribes like the Kacharis, the Lalungs, the Mikirs and others were converted to a new caste, the Koch. Thus the linguistic community which took shape in Brahmaputra valley and came to be known as the Assamese underwent a process of Aryanisation and in the process brought Assam culturally so close to the rest of India that by the 15th century Sankardeva who took pride in the fact that he was born in the ‘Bharatabarsha’."