 In the years leading to the war, the king had been forced to suppress British supported rebellions in his grandfather's western acquisitions (Arakan, Manipur and Assam), but unable to stem cross border raids from British territories and protectorates.His ill-advised decision to allow the Burmese army to pursue the rebels along the vaguely defined borders led to the war.The longest and most expensive war in British Indian history ended decisively in British favor, and the Burmese had to accept British terms without discussion.