Thonburi was founded by a Thai general named Phraya Taksin, who was later crowned King Taksin Maharaj. After the fall of Ayutthaya to the Burmese in 1767, Thonburi, situated on the west bank of the Chao Phraya opposite what is now the City of Bangkok, became the new Thai capital.
After the shattering defeat which had culminated in Ayutthaya's destruction, the death and capture of thousands of Thais by the victorious Burmese, and the dispersal of several potential Thai leaders, the situation seemed hopeless. It was a time of darkness and of troubles for the Thai nation. Members of the old royal family of Ayutthaya had died, escaped, or been captured by the Burmese and many rival claimants for the throne emerged, based in different areas of the country. But out of this national catastrophe emerged yet another saviour of the Thai state - the half-Chinese general Phraya Taksin, former governor of Tak. Within a few years this determined warrior had defeated not only all his rivals but also the Burmese invaders and had set himself up as king,
Since Ayutthaya had been so completely devastated. King Taksin chose to establish his capital at ThonBuri [ across the river from Bangkok ]. Although a small town, ThonBuri was strategically situated near the mouth of the Chao Phraya River and therefore suitable as a seaport. The Thais needed weapons, and one way of acquiring them was through trade. Besides, foreign trade was also needed to bolster the Thai economy, which had suffered extensively during the war with Burma (now Myanmar). Chinese and Chinese-Thai traders helped revive the economy by engaging in maritime trade with neighboring states, with China, and with some European nations.
King Taksin's prowess as a general and as an inspirational leader meant that all attempts by the Burmese to re-conquer Siam failed. The rallying of the Thai nation during a time of crisis was King Taksin's greatest achievement. However, he was also interested in cultural revival, in literature and the arts. He was deeply religious and studied meditation to an advanced level. The stress and strain of such much fighting and the responsibility of rebuilding a centralized Thai state took their toll on the king. Following an internal political conflict in 1782. King Taksin's fellow general Chao Phraya Chakri was chosen king. King Taksin's achievements have caused to bestow on him the epithet "The Great".