The Thonburi Kingdom (ธนบุรี, thōn būrīː), or the Early Bangkok Empire (1767–1851), was a major Siamese kingdom which existed in Southeast Asia from 1767 to 1782, centered around the city of Thonburi, in Siam or present-day Thailand. The kingdom was founded by Taksin the Great, who reunited Siam following the collapse of the Ayutthaya Kingdom, which saw the country separate into five warring regional states. The Thonburi Kingdom oversaw the rapid reunification and reestablishment of Siam as a preeminient military power within mainland Southeast Asia, overseeing the country's expansion to its greatest territorial extent up to that point in its history, incorporating Lan Na, the Laotian kingdoms (Luang Phrabang, Vientiane, Champasak), and Cambodia under the Siamese sphere of influence.
The Thonburi Kingdom saw the consolidation and continued growth of Chinese trade from Qing China, a continuation from the late Ayutthaya period (1688-1767), and the increased influence of the Chinese community in Siam, with Taksin and later monarchs sharing close connections and close family ties with the Sino-Siamese community.
The Thonburi Kingdom lasted for only 14 years, ending in 1782 when Taksin was deposed by a major Thonburi military commander, Chao Phraya Chakri, who subsequently founded the Rattanakosin Kingdom, the fourth and present ruling kingdom of Thailand.
Taksin's reunification of Siam
Phraya Tak, personal name Sin, Zheng Zhao (鄭昭) or Zheng Xin (鄭信), was a nobleman of Teochew Chinese descent. By the time of Burmese Invasion of 1765-1767, Phraya Tak had been the governor of Tak and called to join the defense of Ayutthaya. In January 1767, about three months before the Fall of Ayutthaya, Phraya Tak gathered his own forces of 500 followers and broke through the Burmese encirclement to the east. After battling with Burmese scouting forces and some local resistances, Phraya Tak and his retinue settled in Rayong on the eastern Siamese coast. There, Phraya Tak competed with Pu Lan the Phraya Chanthaburi or the governor of Chanthaburi for domination over the eastern coastline.