Kingdom of Vientiane
In 1764, King Hsinbyushin decided to renew the war against Siam. The king selected Thihapate and Maha Nawrahta as joint commanders to lead another invasion. Thihapate was to lead the northern invasion route from Chiang Mai while Maha Nawrahta was to lead the southern route from Martaban (Mottama). In early 1765, Thihapate with a 20,000-strong force began his operations by starting with the Lao states. The Kingdom of Vientiane agreed to become Burmese vassal without a fight. Luang Prabang resisted but Thihapate's forces easily captured the city in March 1765, giving the Burmese complete control of Siam's entire northern border.