of Burma plus Manipur and Lan Na. However, his hold on Lan Na and Tenasserim coast was still nominal. The Siamese who originally were concerned about the rising power of Restored Hanthawaddy now actively supported the ethnic Mon rebels operating in the upper Tenasserim coast. In December 1759, Alaungpaya and his 40,000-strong armies invaded the Tenasserim coast. They crossed over the Tenasserim Hills, and finally reached Ayutthaya on 11 April 1760. But only five days into the siege, the Burmese king suddenly fell ill and the Burmese withdrew. The king died three weeks later, ending the war. The 1760 war was inconclusive. Although Burma had regained the upper Tenasserim coast to Tavoy, they still had to deal with Siamese supported rebellions in Lan Na (1761–1763) and at Tavoy (1764). The warfare resumed in August 1765, when two Burmese armies invaded again in a pincer movement on the Siamese capital. The Burmese armies took Ayutthaya in April 1767 after a 14-months' siege. The Burmese armies sacked the city and committed atrocities that mar the Burmese-Thai relations to the present. The Burmese were forced to withdraw a few months later due to the Chinese invasions of their homeland. Burma however had annexed the lower Tenasserim coast. Laotian states (1765) Between the two Siamese wars, Burma acquired the Laotian states of Vientiane and Luang Prabang. Vientiane was acquired without a fight in January 1765. Luang Prabang put up a fight but was defeated in March 1765. The move was to outflank Siam in their upcoming invasion. The Laotian states remained Burmese tributaries until 1778. China (1765–1769) Concerned by the Burmese consolidation of Shan states and Laotian states, China launched four invasions of Burma between 1765 and 1769. At first, the Qianlong Emperor envisaged an easy war, and sent in only the Green Standard troops stationed in Yunnan. The Qing invasion came as the majority of Burmese forces were deployed in their latest invasion of Siam. Nonetheless, battle-hardened Burmese troops defeated the first two invasions of 1765–1766 and 1766–1767 at the border. The regional conflict now escalated to a major war that involved military manoeuvres nationwide in both countries. The third invasion (1767–1768) led by the elite Manchu Bannermen nearly succeeded, penetrating deep into central Burma within a few days' march from Ava. But the Bannermen of northern China could not cope with unfamiliar tropical terrains and lethal endemic diseases, and were driven back