The Kingdom of Ayutthaya (Thai: อยุธยา; also spelled Ayudhya or Ayodhaya) was a Siamese kingdom that existed from 1351 to 1767. Ayutthaya was friendly towards foreign traders, including the Chinese, Vietnamese, Indians, Japanese and Persians, and later the Portuguese, Spaniards, Dutch and French, permitting them to set up villages outside the walls of the capital, also called Ayutthaya.
In the sixteenth century, it was described by foreign traders as one of the biggest and wealthiest cities in the East. The court of King Narai (1656–88) had strong links with that of King Louis XIV of France, whose ambassadors compared the city in size and wealth to Paris.
By 1550, the kingdom's vassals included some city-states in the Malay Peninsula, Sukhothai, Lan Na and parts of Burma and Cambodia. This part of the Kingdom's history is sometimes referred to as "The Ayutthayan Empire".
In foreign accounts, Ayutthaya was called Siam, but many sources say the people of Ayutthaya called themselves Tai, and their kingdom Krung Tai "The Tai country" (กรุงไท).
In 1765, a combined 40,000-strong force of Burmese armies invaded the territories of Ayutthaya from the north and west. Major outlying towns quickly capitulated. The only notable example of successful resistance to these forces was found at the village of Bang Rajan. After a 14 months' siege, the city of Ayutthaya capitulated and was burned in April 1767. Ayutthaya's art treasures, the libraries containing its literature, and the archives housing its historic records were almost totally destroyed, and the Burmese brought the Ayutthaya Kingdom to ruin.
The Burmese rule lasted a mere few months. The Burmese, who had also been fighting a simultaneous war with the Chinese since 1765, were forced to withdraw in early 1768 when the Chinese forces threatened their own capital.
With most Burmese forces having withdrawn, the country was reduced to chaos. All that remained of the old capital were some ruins of the royal palace. Provinces proclaimed independence under generals, rogue monks, and members of the royal family.
One general, Phraya Taksin, former governor of Tak, began the reunification effort. He gathered forces and began striking back at the Burmese. He finally established a capital at Thonburi, across the Chao Phraya from the present capital, Bangkok. Taak-Sin ascended the throne, becoming known as King Taak-Sin or Taksin of modern Thailand.