This is the script for my video posted on October 1, 2026. Watch it on TikTok.
If we look at a map of modern Thailand, we’ll see that it’s wedged between former French and British colonies. But if nearly all of southeast Asia was dominated by foreign powers, why is Thailand the exception, and how does this influence its geopolitical dynamics?
Thai history really begins with a migration. See, the ancestors of the Thai people originally lived in what's now southern China, and sometime between roughly the 8th and 13th centuries they began moving south and settling among the existing Mon and Khmer civilizations.
City-states and regional river-valley kingdoms formed, including the Sukhothai Kingdom, traditionally dated to 1238, often considered the cradle of a distinctive Thai cultural and religious identity built around Theravada Buddhism.
In 1351, a ruler named U Thong founded the kingdom of Ayutthaya and its capital city of the same name, uniting polities around the Chao Phraya River basin and other regional centers. The kingdom grew quickly, absorbing Sukhothai by 1438 and building a strong centralized state. Europeans called this kingdom Siam, and its heartland makes up much of modern Thailand.
Ayutthaya was the Siamese capital for centuries, but in 1767, after a 14-month siege, the Burmese army captured the city and burned it. The Burmese soon pulled most of their troops home to fight a Chinese invasion, and a general named Taksin drove out the rest and ruled from a new capital at Thonburi.
In 1782, Taksin was overthrown, and the new king, Rama the First, moved the capital across the river to Bangkok.
Still, Siam bounced back, taking tribute payments from Cambodia, the Lao kingdoms, the Malay sultanates, and other polities. At the time, it was common for smaller states to pay tribute to several powers at once in exchange for protection and the freedom to run their own affairs. But this effectively gave multiple countries a claim on the same place, and when European colonial powers arrived with their fixed borders, those overlapping claims turned into tangible conflicts.
Shortly after Siam's capital moved to Bangkok, the British began expanding into the region. They acquired Penang in 1786, put settlements along the Strait of Malacca by 1826, and took Burma in three bites between 1824 and 1885. And all along the way, British firms came to dominate the regional trade in rice, teak, and tin.
France began its push into the region in 1858, conquering Cochinchina, now southern Vietnam, and then making Cambodia, Annam, and Tonkin into protectorates. In 1887, it combined these colonies and protectorates into the Indochinese Union, better known as French Indochina. The French wanted to match British influence and open a river route to China via the Mekong, though in reality the upper Mekong was largely impassable thanks to strong rapids.
Meanwhile, Britain was becoming the region's economic powerhouse by pushing free trade, often at gunpoint, as it had done to China in the First Opium War. Siam had watched China lose that war, so when Britain's envoy John Bowring arrived in 1855, King Mongkut decided to buy in, both to avoid a war and because he expected free trade to bring in more revenue.
Under the Bowring Treaty, Siam replaced its royal trade monopolies and old duties with a three percent cap on import duties and a single tax on exports. It allowed rice exports except during shortages, which plugged Siam into regional and global shipping markets. And controversially, it let British merchants import opium duty-free, as long as they sold it only to the government's licensed opium dealer.
It also gave British subjects extraterritoriality, meaning they were tried by a British consul under British law instead of in Siamese courts, and it let British merchants live permanently in Bangkok and buy land around the city under some restrictions. All told, this gave Britain most of what it would have wanted from a colony without the cost of running one, so it didn't need to rule Siam directly, at least for the time being.
Over the next few decades, Mongkut and especially his son Chulalongkorn made Siam structurally more like a European state. They did it partly to strengthen the crown at home and partly to prove to the colonial powers that Siam didn't need to be taken over.
They created Western-style government ministries and replaced hereditary lords and tributary rulers with governors sent from Bangkok. They gradually abolished slavery, starting in 1874. And they built a Western-style military, including a navy with many Danish officers, and began writing modern legal codes. All of this aimed at convincing Europe to give back Siam's control over foreigners on its soil and over its own economy.
Of course, things didn't always come easy, largely thanks to France. In 1893, France claimed the Mekong as its territorial limit, sent troops to take the land east of the river, and naturally clashed with Siamese forces.
That July, two French gunboats forced their way past the river forts at Paknam under fire and anchored in Bangkok within range of the royal palace. France issued an ultimatum, and when Siam offered to give up only part of the territory, France blockaded the coast around Bangkok.
Britain refused to use its gunboats even though the blockade was hurting British trade, and in fact it pressed Siam to give in. Within days of the blockade, Siam accepted France's terms in full. In the treaty that October, it renounced its claim to all territory on the east bank of the Mekong and the islands in the river.
It also agreed to a 25-kilometer demilitarized zone along the west bank and paid France three million francs. On top of that, it had to accept French troops occupying the port town of Chanthaburi as a guarantee. King Chulalongkorn reportedly fell into illness and depression afterward.
That crisis worried Britain too, since it didn't want France swallowing Siam and sitting on the doorstep of British Burma and Malaya. So in 1896, Britain and France signed a declaration without consulting Siam, promising that neither would send armed forces into Siam's heartland around the Chao Phraya River without the other's consent.
The declaration left France's rights from the 1893 treaty intact and barred either side from letting a third power in through a separate deal. But it still allowed joint action if both agreed it was needed to uphold Siam's independence. See, this is the real answer to our question. Siam survived largely because Britain and France each preferred it as a buffer to having the other's empire right next door.
But that buffer only covered the core. In 1904, Siam ceded more land on the west bank of the Mekong to France. That same year, Britain and France settled their colonial rivalries with a set of agreements called the Entente Cordiale, which treated western Siam as a British sphere of influence and eastern Siam as a French one. Siam then gave up western Cambodian provinces to France in 1907, and four northern Malay sultanates to Britain in 1909.
In each deal, Siam traded land for something it wanted, like the return of occupied towns or rolling back foreigners' special legal status. From 1893 to 1909, Siam gave up claims to a huge area, by some estimates a third or more of the territory it once claimed, though much of it was only loosely held through tributaries. But it kept its independence, even though full sovereignty didn't come until the late 1930s, when the last special legal privileges for foreigners ended.
There's a lot more history to cover around and after the first and second World Wars. Siam joined the Allies in World War One, declaring war on Germany in 1917 and sending troops to France, which gave it leverage to start renegotiating those unequal treaties. In 1939, it changed its name to Thailand.
When France fell to Germany in 1940, Vichy France struggled to control French Indochina. Thailand capitalized on this by fighting a short war, and in 1941 a deal brokered by Japan gave it land in Laos and western Cambodia. Then Japan invaded Thailand that December, and Thailand allied with Japan and declared war on the US and Britain. But its ambassador in Washington, DC refused to deliver the declaration, so the US never declared war back. After the war, Thailand returned those territories to France, and today they're part of Cambodia and Laos.
So basically, Thailand avoided colonization for two reasons. Britain and France each preferred it as a buffer, and its kings cooperated, reformed, and gave up land on the edges to protect the core. But in reality its sovereignty was limited for decades, and it was still very much entangled with colonial interests.
At the same time, Thai leaders consistently moved to protect their own interests and capitalized on shifting geopolitical conditions to make gains. That habit lives on in what's now called bamboo diplomacy: Thailand bends with the wind rather than breaking.
Keep reading
- How did Vietnam become friends with everyone?
- How did Japan end up controlling China’s gateway to the Pacific?
- Why is Sri Lanka so important?
I’m writing a book called Groundwork about the buried history beneath geopolitics. Join the waitlist to hear when it has a publisher, a cover, and a release date.