The early 16th century Portuguese first contact with Siam ushered in the era of colonialism in the region. For the next four centuries Siam would be a pawn in the French and British games of dominance over the region. France gained possession of Cambodia, and the British responded with a foothold in the Malay peninsula through treaties. The British established an embassy in Siam but kept the country independent to act as a buffer state next to their colonies in Burma and Malaya. By the early decades in the 1900s a wave of nationalism swept off both British and French from the region, and Siam’s military government leader changed the country’s name to commemorate the event.

On this day, June 24, in 1939, Field Marshal Muang Thai, the prime minister and leader of the military junta running the government renamed the country Prathet Thai — land of the Thais (“Thai” also meaning “free”).

Japan succeeded the British and French as the dominant military force in the region by that time, and the Thais allied with Japan partly out of self-preservation, partly because Japan’s seemingly likely victory would allow Thailand to regain its former territories in Cambodia, Laos and Burma. After Japan’s surrender, the Allied powers concluded Thailand acted under duress, and the country escaped occupation. Thailand’s anti-China stance came in very useful to the Allies later on.