The map shows how the original Kingdom of Siam was once significantly larger than present-day Thailand, with territories extending into what are now parts of Laos, Cambodia, Myanmar, and Malaysia. At its peak, Siam controlled a vast region of mainland Southeast Asia. However, during the colonial era in the 19th and early 20th centuries, it faced pressure from stronger European powers, mainly France and the United Kingdom, who were expanding their empires.

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Over time, Siam was forced to cede large portions of its land to avoid full colonization. France took over territories to the east, including Laos and parts of Cambodia, while Britain claimed areas to the west and south, including parts of Myanmar and the Malay Peninsula. These losses were part of strategic negotiations that allowed Siam to remain independent, unlike its neighbors who were colonized.

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Eventually, on June 23, 1939, Siam officially changed its name to Thailand, meaning "Land of the Free." This change marked a new era of national identity following decades of political reform and territorial compromise. Despite the losses, Thailand remains the only country in Southeast Asia that was never formally colonized by a European power.