* Ancient Kingdoms: The region now known as Thailand has been home to various kingdoms and empires for centuries. The Sukhothai Kingdom (1238-1438) is often seen as the beginning of a unified Thai identity.
* Ayutthaya Kingdom: This powerful kingdom (1351-1767) consolidated much of the region and expanded Thai influence.
* Modern Era: After a period of decline and foreign rule, the Chakri Dynasty established the Kingdom of Siam (1782).
* Name Change: In 1939, the name Siam was officially changed to Thailand, though the country remained a monarchy.
So, to answer your question more accurately, it depends on how you define "became a country":
* Early Unification: You could argue that Thailand "became a country" around the time of the Sukhothai Kingdom (13th century).
* Modern Nation-State: The establishment of the Kingdom of Siam in 1782 marks a significant turning point towards a modern, unified state.
* Name Change: The adoption of the name Thailand in 1939 signifies a shift towards a more modern and self-defined national identity.
Ultimately, Thailand's history is a continuous evolution, making it hard to assign a single year for its "birth" as a country.