The history of Thailand

Thailand, known until 1939 as Siam, is the only country in South-east Asia that was never colonised by a European power. Before the Tai peoples arrived, its lands were home to Bronze Age villages, Mon kingdoms and the provinces of the Khmer Empire. From the thirteenth century Tai kingdoms rose at Sukhothai, Chiang Mai and above all Ayutthaya, which for four centuries was one of the great trading states of Asia until Burmese armies destroyed it in 1767. The Chakri dynasty, ruling from Bangkok since 1782, kept Siam independent by modernising it and giving up border territories to Britain and France. Since the end of absolute monarchy in 1932, the country has swung between elected governments and military rule, with a dozen successful coups.

People have lived in what is now Thailand for tens of thousands of years, and the Spirit Cave in the north-west preserves traces of hunter-gatherers from around 10,000 years ago. Rice farming spread into the region from the north in the third millennium BCE. At Ban Chiang, in the north-east, villagers were casting bronze by around 1500 BCE, and the site's burials, with their painted red-on-buff pottery, are among the best-known in South-east Asia. Iron came into use in the first millennium BCE. By the early centuries CE, trade with India brought new religions, scripts and ideas of kingship, while Chinese records describe the first organised states of the region, such as Funan on the lower Mekong.

From the sixth to the tenth century the Chao Phraya basin was home to the Dvaravati culture, a network of city-states such as Nakhon Pathom and U Thong. Its people were Mon, and inscriptions and art show that they practised Theravada Buddhism learned from Sri Lanka and India, alongside Hindu rites at court. In the north the Mon kingdom of Hariphunchai, at modern Lamphun, was a centre of Buddhism. On the Malay Peninsula, trading states such as Tambralinga and Langkasuka controlled routes across the isthmus, and many fell under the influence of Srivijaya, the Sumatran maritime empire. In the eleventh century the Chola dynasty of southern India raided the region.

From the tenth century the Khmer Empire of Angkor expanded west. Lopburi, then called Lavo, became a provincial centre, and Khmer temples such as Phanom Rung and Phimai were built in the north-east. Khmer art, Hindu-Buddhist kingship and court language left a deep mark on later Thai culture.

The Tai peoples, speakers of Kra-Dai languages, originated in what is now southern China and northern Vietnam. Over the first millennium CE and after, they moved south-west along river valleys into the uplands of modern Laos, Myanmar and northern Thailand, forming small principalities called muang. They mixed with the Mon and Khmer peoples and adopted Theravada Buddhism.

Around 1238 two Tai chiefs threw off Khmer rule at Sukhothai, on the northern edge of the central plain, and one became its first king. Under Ram Khamhaeng, at the end of the thirteenth century, Sukhothai extended its influence over a wide area and sent missions to the Yuan dynasty in China. Thai tradition credits him with creating the Thai script in 1283, though the famous inscription in his name has been debated by scholars. Sukhothai's later kings were great patrons of Buddhism, but the kingdom declined in the fourteenth century and became a vassal of Ayutthaya, which absorbed it in 1438.

In the north, King Mangrai united the Tai of the upper Ping valley, conquered Hariphunchai in the 1290s and founded Chiang Mai in 1296 as the capital of Lan Na, the "kingdom of a million rice fields". Lan Na developed its own script and Buddhist culture and remained a separate kingdom for centuries, fighting Ayutthaya and falling under Burmese rule in 1558.

In 1351 a ruler known as U Thong founded the Ayutthaya Kingdom on an island in the Chao Phraya river, well placed for trade with the sea. Ayutthaya combined Tai rule with Khmer court traditions, in which the king was a remote and sacred figure. It sacked Angkor in 1431, after which the Khmer court moved south towards Phnom Penh, and under King Trailok in the fifteenth century it organised its society through the sakdina system, which gave every person a rank measured in units of land.

Ayutthaya grew rich from trade, exporting rice, deerskins, sappanwood and forest goods, and welcomed merchants from China, Japan, India, Persia and Europe. The Portuguese arrived in 1511, after taking Malacca, and were followed by the Dutch, English and French. It also fought long wars with Burma. In 1569 the Burmese king Bayinnaung captured the city and made it a vassal, but in 1584 Prince Naresuan declared independence, and in 1593 he is said to have killed the Burmese crown prince in a duel on elephants. King Narai, who reigned from 1656 to 1688, exchanged embassies with Louis XIV of France and employed the Greek adventurer Constantine Phaulkon as a minister, but fear of French influence led to a palace revolution in 1688, after which Ayutthaya kept Europeans at a greater distance. The city, with perhaps a population in the hundreds of thousands, remained one of the largest in Asia. In 1765 the Konbaung dynasty of Burma invaded again, and after a long siege Ayutthaya fell in April 1767. The city was burned, its temples looted and tens of thousands of people carried off to Burma.

A half-Chinese general, Taksin, gathered an army, drove out the Burmese garrisons and reunited the kingdom within a few years, ruling from Thonburi on the Chao Phraya. In 1782 he was deposed and executed, and his leading general became king as Rama I, founding the Chakri dynasty that still reigns. He moved the capital across the river to Bangkok, building the Grand Palace and the Temple of the Emerald Buddha. The early Chakri kings defeated further Burmese invasions, brought Lan Na, Laos and parts of Cambodia and the northern Malay sultanates under their overlordship, and fought Vietnam for control of Cambodia. In 1827 King Anouvong of Vientiane rebelled, and Siamese forces destroyed his city and deported much of its population. Trade with China grew, and many Chinese settled in Bangkok.

By the mid-nineteenth century the British Empire had conquered lower Burma and Malaya was in reach. King Mongkut, Rama IV, a former monk who had studied Western science and languages, chose to open the country. In 1855 he signed the Bowring Treaty with Britain, which ended royal trading monopolies, fixed low import duties and gave British subjects the right to be tried in their own consular courts. Similar treaties followed with other Western powers, and rice exports soared.

His son Chulalongkorn, Rama V, who reigned from 1868 to 1910, transformed the state. He abolished slavery and forced labour in stages, created ministries on Western lines, built railways and telegraphs, founded modern schools and replaced the old semi-independent provincial lords with salaried governors controlled from Bangkok. Siam's survival also depended on concessions. In the Franco-Siamese crisis of 1893, French gunboats forced their way up the Chao Phraya to Bangkok, and Siam gave up its claims east of the Mekong to French Indochina, now part of Laos. Further treaties in 1904 and 1907 ceded more land west of the Mekong and the western Cambodian provinces of Battambang and Siem Reap to France, and the Anglo-Siamese Treaty of 1909 transferred four northern Malay states, Kedah, Perlis, Kelantan and Terengganu, to British rule in what is now Malaysia. An Anglo-French agreement of 1896 had already accepted Siam as a buffer between their empires.

King Vajiravudh, Rama VI, promoted a nationalism centred on nation, religion and king, and in 1917 brought Siam into the First World War on the Allied side, which helped it win the gradual abolition of the unequal treaties in the 1920s and 1930s.

The Great Depression hit Siam's rice economy and royal finances hard. On 24 June 1932 the People's Party, a group of civil servants and officers educated in Europe, seized power without bloodshed and forced King Prajadhipok to accept a constitution. Its civilian leader Pridi Banomyong proposed far-reaching economic reforms, while the military wing grew dominant. Royalists rose in the Boworadet rebellion of 1933 and were defeated, and in 1935 Prajadhipok abdicated in favour of his young nephew Ananda Mahidol.

Field Marshal Plaek Phibunsongkhram, known as Phibun, became prime minister in 1938 and promoted an assertive nationalism. In 1939 the country's name was changed to Thailand. After the fall of France in 1940, Thailand fought a short war with the Vichy French authorities in Indochina and, through Japanese mediation, regained parts of Laos and Cambodia. On 8 December 1941, as the Second World War reached Asia, troops of the Empire of Japan landed in Thailand. Phibun allowed them through to attack British Malaya and Myanmar, then known as Burma, and in 1942 declared war on Britain and the United States. The Thai ambassador in Washington, Seni Pramoj, refused to deliver the declaration and organised the Free Thai movement with Pridi, who led its underground at home. Tens of thousands of Asian labourers and Allied prisoners of war died building the Japanese railway from Thailand to Burma. Because of the Free Thai resistance, the United States treated Thailand as an occupied country rather than an enemy after the war, and Thailand returned the territories it had taken.

King Ananda was found shot dead in the palace in June 1946, a death that has never been fully explained, and his brother Bhumibol Adulyadej succeeded him. A coup in 1947 brought the army back to power, and Phibun returned as prime minister. In 1957 Field Marshal Sarit Thanarat seized power and ruled as a dictator, promoting economic development and restoring the monarchy's public prestige.

During the Cold War Thailand became a close ally of the United States. It joined the Southeast Asia Treaty Organisation in 1954, and during the Vietnam War American aircraft flew bombing missions over Vietnam and Laos from Thai bases, while tens of thousands of American servicemen were stationed in the country. American aid and investment fuelled the growth of Bangkok. The Communist Party of Thailand waged an insurgency from 1965, mainly in the north-east and the north, which faded after an amnesty in 1980.

On 14 October 1973 huge student-led demonstrations in Bangkok, in which dozens of people were shot dead, forced the military rulers Thanom Kittikachorn and Praphas Charusathien into exile. Three years of open democracy followed, but on 6 October 1976 police and right-wing militias attacked students at Thammasat University, killing at least 46 people, and the army took power again. Under General Prem Tinsulanonda, prime minister from 1980 to 1988, Thailand moved towards a semi-democracy, and in the late 1980s it was one of the fastest-growing economies in the world. When the general Suchinda Kraprayoon made himself prime minister after a coup in 1991, mass protests in May 1992 were put down with deadly force until King Bhumibol intervened, and civilian government was restored.

A new constitution in 1997, drafted with wide public involvement, was followed months later by the Asian financial crisis, which began with the collapse of the Thai baht in July 1997. In 2001 the telecoms billionaire Thaksin Shinawatra became prime minister. His policies of cheap health care and village funds made him hugely popular among the rural poor of the north and north-east, but critics accused him of corruption and authoritarianism, and his heavy-handed response to a renewed Malay Muslim insurgency in the far south, from 2004, worsened a conflict that has since killed thousands. The army ousted Thaksin in a coup in September 2006, and for years supporters of Thaksin, the "red shirts", and his royalist opponents, the "yellow shirts", fought for power in the streets and the courts. In 2010 an army crackdown on red-shirt protests in Bangkok left around 90 people dead.

Thaksin's sister Yingluck Shinawatra won the 2011 election, but after months of protests the army under General Prayut Chan-o-cha seized power on 22 May 2014. King Bhumibol, the world's longest-reigning monarch at the time, died on 13 October 2016 after seventy years on the throne, and his son Maha Vajiralongkorn became king. A constitution drafted under the junta in 2017 gave an appointed senate a say in choosing the prime minister, and Prayut remained in office after the 2019 election. In 2020 youth-led protests made unprecedented public calls to reform the monarchy, and many protesters were later prosecuted under the strict lèse-majesté law.

The reformist Move Forward Party won the most seats in the 2023 election, but the senate blocked its leader from becoming prime minister. Pheu Thai, the party of the Shinawatra family, formed a coalition with conservative parties, and Thaksin returned from exile. In 2024 the Constitutional Court dissolved Move Forward over its plan to amend the lèse-majesté law, and removed Prime Minister Srettha Thavisin, who was succeeded by Thaksin's daughter Paetongtarn Shinawatra. In January 2025 a law allowing same-sex marriage took effect, the first in South-east Asia.

A long-running border dispute with Cambodia erupted into fighting in July 2025, with air strikes and artillery, before a ceasefire mediated in Malaysia. A leaked phone call between Paetongtarn and the Cambodian leader Hun Sen led the Constitutional Court to remove her from office, and in September 2025 Anutin Charnvirakul of the conservative Bhumjaithai Party became prime minister. Fighting with Cambodia flared again in December 2025 before a second ceasefire. Anutin dissolved parliament, and in the general election of 8 February 2026 Bhumjaithai won the most seats, ahead of the People's Party, Move Forward's successor. Anutin formed a coalition with Pheu Thai and was re-elected prime minister in March 2026.