states and eliminating all threats to his new rule by 1771. The Burmese, all the while, were preoccupied defeating a fourth Chinese invasion of Burma by December 1769. By then, a new stalemate had taken hold. Burma had annexed the lower Tenasserim coast but again failed to eliminate Siam as the sponsor of rebellions in her eastern and southern borderlands. In the following years, Hsinbyushin was preoccupied by the Chinese threat, and did not renew the Siamese war until 1775—only after Lan Na had revolted again with Siamese support. The post-Ayutthaya Siamese leadership, in Thonburi and later Rattanakosin (Bangkok), proved more than capable; they defeated the next two Burmese invasions (1775–1776 and 1785–1786), and vassalized Lan Na in the process. Background 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,