Explanation:

Purandar Singha was the last king of Ahom kingdom in Assam. He was installed as king twice. First time, he was installed by Ruchinath Burhagohain in 1818 CE, after the latter deposed Chandrakanta Singha from the throne. His first reign ended in 1819 CE, during the second Burmese invasion of Assam, when his forces were defeated and the Burmese reinstalled Chandrakanta Singha on the throne. He along with Ruchinath Burhagohain continued their efforts to expel Burmese invaders, by seeking help from British and through armed struggle. After First Anglo-Burmese War, the British East India Company occupied Assam from Burmese invaders. Finding it difficult to administer an unfamiliar region and sensing discontent among the local inhabitants to foreign rule, the British authorities decided to restore Upper Assam to one prince of Ahom Dynasty. Purander Singha was found suitable for this post and therefore, in April 1833 CE, except Sadiya and Matok region, the entire Upper Assam was formally made over to him, on the condition of yearly tribute of 50,000 rupees. Later, in 1838 CE, finding him incompetent and defaulter in payments of revenue, the British formally annexed his kingdom, putting an end to 600 years reign of Ahom Dynasty. When Purandar Singha accepted the position of prince over upper Assam, he didn't realize the difficulties of his new position.