withdrew in disarray in late January 1786. So severe was the defeat that the invasion turned out to be the last full-scale invasion of Siam by Burma. Siam was now on the offensive, and tried to regain the Tenasserim coast they had lost since 1765. In 1787, its forces laid siege to Tavoy but were unsuccessful. In March 1792, they got the governor of Tavoy to switch sides, and sent in a large army to retake Tenasserim. But the Siamese could not take Mergui and had to lay siege to the city. Initial Burmese efforts to retake Tavoy failed. The Burmese sent in another force after the rainy season and in December, recovered Tavoy and relieved Mergui which had held on for nine months. Having failed in the south, Siam then tried north. After the 1786 war, Siam consolidated its control of Lan Na, and in 1794, took over the Laotian state of Luang Prabang, its erstwhile ally against the Burmese. In response, Burma sent in a small expedition in 1797 to Chiang Mai and Luang Prabang to check the Siamese but it failed to make any impression. Undeterred, the Siamese army invaded Burmese territories of Kengtung and Kenghung (Sipsongpanna) in November 1803, laying siege to both towns. They withdrew in early 1804, taking back many conscripts with them. Burmese forces followed up on the retreating Siamese into Lan Na but were driven back at Chiang Saen at the border. Siam did not give up. In 1807–1808, Siamese troops based out of their vassal Luang Prabang tried to take over Sipsongpanna but were driven back. (In 1822, they again encouraged the ruler of Sipsongpanna to revolt. Burmese troops from Kengtung arrested the rebel sawbwa.) While Siam was focused on extending its northern border, Burma was focused on extending its southern border. Burma sent four expeditions between 1809 and 1812 to take the tin rich Junkceylon island. Aside from a few temporary victories and the sacking of Thalang, the army was driven back each time. Manipur (1814–1820) After the four failed expeditions on Junkceylon, Bodawpaya gave up on wars with Siam, and now looked to the small states to the west. The first target was Manipur, which had regained independence from Burma since 1782. In February 1814, he sent an expedition force to place his nominee Marjit Singh to the Manipuri throne. The Manipuri army was defeated after heavy fighting, and