The post-Ayutthaya Siamese leadership proved more than capable; they defeated the next two invasions (1775–1776 and 1785–1786), and annexed Lan Na in the process. The Burmese–Siamese War (1765–1767) was the continuation of the war of 1759–1760, the "casus belli" of which was a dispute over the control of the Tenasserim coast and its trade, and Siamese support for ethnic Mon rebels of the fallen restored Hanthawaddy Kingdom of Lower Burma. The 1760 war, which claimed the life of the dynasty founder King Alaungpaya, was inconclusive. Although Burma regained control of the upper Tenasserim coast to Tavoy, it achieved none of its other objectives. Following the war, the new Burmese king, Naungdawgyi, was beset with rebellions in Ava and Toungoo, and instabilities spread to the border regions. Lan Na (Chiang Mai) was in open rebellion (1761–1763) with active Siamese support. (Siam even sent an army in support of the rebels. However, the Siamese chronicles claim that the army did not engage in the fighting because the Burmese army had already defeated the rebellion.) In the Burmese south too, the Siamese readily provided shelter to the defeated ethnic Mon rebels who had unsuccessfully rebelled in 1762. Things calmed down after the Lan Na rebellion was suppressed in January 1763. Naungdawgyi, who had been putting down multiple rebellions since his accession, was eager to lead a peaceful reign. He chose not to renew a war with Siam despite Siam's active support of the Lan Na rebellion and continued sheltering Mon rebels. Naundawgyi died in November 1763, and was succeeded by his brother Hsinbyushin who had wanted to continue the war with Siam since the end of the last war. The Siamese leadership was alarmed by Hsinbyushin's accession. Knowing that another war was inevitable, the Siamese leadership accelerated their policy of keeping Burmese regions unstable. In mid-1764, the Siamese successfully encouraged the ethnic Mon governor of Tavoy, who was appointed by Alaungpaya only four years earlier, to switch sides. Hsinbyushin was forced to send an army led by Maha Nawrahta, who retook Tavoy in November 1764.