The Koch–Ahom conflicts (1543–68) refer to the rivalry between the Koch and the Ahom kingdoms over the control of the Brahmaputra Valley. The conflict began with Nara Narayana ascending to power and consolidating his hold over the western portion; and it ended with the failure of Chilarai's campaign against Sulaiman Karrani. This was followed by an alliance that soon gave away to a fierce conflict between the Ahoms and the Mughals.
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Koch–Ahom conflicts Wikipedia(Text) CC BY-SA