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.

Despite these successes, by 1779 Taksin was in political trouble at home. He seems to have developed a religious mania, alienating the powerful Buddhist monkhood by claiming to be a sotapanna or divine figure. He also attacked the Chinese merchant class, and foreign observers began to speculate that he would soon be overthrown. In 1782 Taksin sent his armies under Chakri to invade Cambodia, but while they were away a rebellion broke out in the area around the capital. The rebels, who had wide popular support, offered the throne to Chakri. Chakri marched back from Cambodia and deposed Taksin, who was secretly executed shortly after.

Chakri ruled under the name Ramathibodi (he was posthumously given the name Phutthayotfa Chulalok), but is now generally known as King Rama I, first king of the Chakri dynasty. One of his first decisions was to move the capital across the river to the village of Bang Makok (meaning "place of olive plums"), which soon became the city of Bangkok. The new capital was located on the island of Rattanakosin, protected from attack by the river to the west and by a series of canals to the north, east and south. Siam thus acquired both its current dynasty and its current capital.

References :Thongchai Winichakul. Siam Mapped. University of Hawaii Press, 1984.Wyatt, David. Thailand: A Short History (2nd edition). Yale University Press, 2003.