Thonburi period
In 1767, after dominating southeast Asia for almost 400 years, the Ayutthaya kingdom was brought down by invading Burmese armies, its capital burned, and its territory occupied by the invaders
Despite its complete defeat and occupation by Burma, Siam made a rapid recovery. The resistance to Burmese rule was led by a noble of Chinese descent, Taksin, a capable military leader. Initially based at Chanthaburi in the south-east, within a year he had defeated the Burmese occupation army and re-established a Siamese state with its capital at Thonburi on the west bank of the Chao Phraya, 20 km from the sea. In 1768 he was crowned as King Taksin (now officially known as Taksin the Great). He rapidly re-united the central Thai heartlands under his rule, and in 1769 he also occupied western Cambodia. He then marched south and re-established Siamese rule over the Malay Peninsula as far south as Penang and Terengganu. Having secured his base in Siam, Taksin attacked the Burmese in the north in 1774 and captured Chiang Mai in 1776, permanently uniting Siam and Lanna. Taksin's leading general in this campaign was Thong Duang, known by the title Chaophraya Chakri. In 1778 Chakri led a Siamese army which captured Vientiane and re-established Siamese domination over Laos.