The history of Thailand begins with the migration of the Tai- Lao speaking people from their ancestral home in southern China into mainland southeast Asia around the 10th century AD. Prior to this, Mon, Khmer and Malay kingdoms ruled the region. The Thais established their own states starting with Sukhothai, Chiangsaen and Chiangmai as Lanna Kingdom and then Ayutthaya kingdom. These states fought each other and were under constant threat from the Khmers, Burma and Vietnam. Much later, the European colonial powers threatened in the 19th and early 20th centuries, but Thailand survived as the only Southeast Asian state to avoid colonial rule. After the end of the absolute monarchy in 1932, Thailand endured sixty years of almost permanent military rule before the establishment of a democratic elected-government system.

Initial states of Thailand

Prior to the southwards migration of the Tai people from Yunnan in the 10^th century, the Indochina peninsula had been a home to various indigenous animistic communities for as far back as 500,000 years ago. The recent discovery of Homo erectus fossils such as Lampang man is but one example. The remains were first discovered during excavations in Lampang province, Thailand. The finds have been dated from roughly 1,000,000-500,000 years ago in the Pleistocene.There are myriad sites in Thailand dating to the Bronze (1500 BC-500 BC) and Iron Ages (500 BC-AD 500). The most thoroughly researched of these sites are located in the country's Northeast, especially in the Mun and Chi River valleys. The Mun River in particular is home to many 'moated' sites which comprise mounds surrounded by ditches and ramparts. The mounds contain evidence of prehistoric occupation.

Around the first century of the Christian era, rding to Funan epigraphy and the records of Chinese historians(Coedes), a number of trading settlements of the South appear to have been organized into several Indianised states, among the earliest of which are believed to be Langkasuka and Tambralinga.

Dvaravati

Dvaravati first came to the attention of modern scholars during the 19th century through the translation of Chinese texts. These texts mentioned To-lo-po-ti, Tu-ho-po-ti and Tu-ho- lo-po-ti, names that were translated into Sanskrit- Dvaravati. We know that this polity had an international presence, as it sent a number of missions to the Chinese court, but it is difficult to reconstruct what kind of polity is represented and scholarly opinion is split.
Clearly the issue cannot be resolved until further research is undertaken but the current evidence appears to favour an interpretation of Dvaravati as a loosely organized political entity at a pre-state level, heavily influenced by Buddhism, due to the ruins and artifacts found.

The situation is confused further by the use of the term Dvaravati to describe a school of art and a culture, uniquely different from Angkorian Khmer art. It is best to consider Dvaravati as a broad term, encompassing all of these things, a culture, comprised mostly of Mon speakers who produced predominantly religious art and lived in large towns concentrated in the Chao Phraya Valley whose influence extended into other parts of Thailand. Possibly Dvaravati's entity spanned from Andaman coast in the west to Chao Phraya valley, across the mountain range into the northeastern region. However its influence was likely in wane after the rise of Angkor. Then the upper mainland was seen under Khmer Angkor's influence.

Sukhothai and Lanna

Thai city-states gradually became independent from the weaker Khmer Empire. It is said that Sukhothai was established as a sovereign, strong kingdom by Pho Khun Si Indrathit in 1238. A political feature called by 'classic' Thai historians as, 'father governs children' existed at this time. Everybody could bring their problems to the king directly; as there was a bell in front of the palace for this purpose. The city briefly dominated the area under King Ramkhamhaeng, who established the Thai alphabet, but after his death in 1365 it fell into decline and became subject to another emerging Thai state, Ayutthaya kingdom, in the lower Chao Phraya area.

Another Thai state that coexisted with Sukhothai was the northern state of Lanna, centered in Chiangmai. King Phya Mangrai was its founder. This state emerged in the same period as Sukhothai. Evidently Lanna became closed ally of Sukhothai. When Ayutthaya kingdom had emerged and expanded its influence from the Chao Phraya valley, Sukhothai was finally subdued. Fierce battles between Lanna and Ayutthaya had constantly took place. Chiangmai was eventually subjugated, becoming Ayutthaya's 'vassal'.

Lanna's independent history ended in 1558, when it finally fell to the Burmese; thereafter it was dominated by Burma until late eigthteenth century. Local leaders rose up against the Burmese with the help of the rising Thai kingdom of Thonburi king Taksin. The 'Northern City-States' then became vassals of the lower Thai kingdoms of Thonburi and Bangkok. In early twentieth century they were annexed and became part of modern Siam, or Thailand.

Ayutthaya

Ayutthaya Kingdom has its location on a small inlet, circled by three rivers. Due to its superior location, Ayutthaya quickly became powerful, politically and economically. Ayutthaya had different, various names ranging from 'Ayothaya', derived from Ayodhya, an Indian holy city,'Krung Thep', 'Phra Nakorn' and 'Dvaravati'.

The first ruler of the Kingdom of Ayutthaya, King Ramathibodi I, made two important contributions to Thai history: the establishment and promotion of Theravada Buddhism as the official religion – to differentiate his kingdom from the neighbouring Hindu kingdom of Angkor – and the compilation of the Dharmashastra, a legal code based on Hindu sources and traditional Thai custom. The Dharmashastra remained a tool of Thai law until late in the 19th century. However Ayutthaya was plagued by internal fighting

Ayutthaya's tradition became the model for later period, Bangkok's Chakri Dynasty.

Beginning with the Portuguese in the 16th century, Ayutthaya, known to the Europeans as 'Kingdom of Siam', had some contact with the West. It became one of the most prosperous cities in East Asia. Dutch and French were among the most active foreigners in the kingdom as well as Chinese and Japanese.

Ayutthaya expanded its sphere over a considerable area, ranging from the Islamic states on the Malay Peninsula, the Andaman ports, to states in northern Thailand. In the 18th century, Ayutthaya Kingdom was gradually in decline as fighting between princes and officials had plagued its political arena. Outlying principalities became more and more independent, ignoring the capital's orders and decrees.

In the 1700s, the last phase of the kingdom arrived. The Burmese, who had control of Lanna and had also unified their kingdom under a powerful dynasty, launched several invasion attempts in the 1750s and 1760s. Finally, in 1767, the Burmese attacked the capital city and conquered it. The royal family fled the city where the king died of starvation ten days later. The Ayutthaya royal line had been extinguished. Overall there are 33 kings in this period, including an unofficial king.

There were 5 dynasties during Ayutthaya period:

• U-Thong Dynasty which consists of 3 kings

• Suphanabhumi Dynasty consisting of 13 kings

• Sukhothai Dynasty consisting of 7 kings

• Prasart Thong (Golden Tower) Dynasty consisting of 4 kings

• Bann Plu Dynasty consisting of 6 kings

Thonburi and Bangkok period

After more than 400 years of power, in 1767, the Kingdom of Ayutthaya was brought down by invading Burmese armies, its capital burned, and the territory split. General Taksin managed to reunite the Thai kingdom from his new capital of Thonburi and declared himself king in 1769. However, Taksin allegedly became mad, and he was deposed, taken prisoner, and executed in 1782. General Chakri succeeded him in 1782 as Rama I, the first king of the Chakri dynasty. In the same year he founded the new capital city at Bangkok, across the Chao Phraya river from Thonburi, Taksin's capital. In the 1790s Burma was defeated and driven out of Siam, as it was then called. Lanna also became free of Burmese occupation, but the king of a new dynasty who was installed in the 1790s was effectively a puppet ruler of the Chakri monarch.

The heirs of Rama I became increasingly concerned with the threat of European colonialism after British victories in neighboring Burma in 1826. The first Thai recognition of Western power in the region was the Treaty of Amity and Commerce with the United Kingdom in 1826. In 1833, the United States began diplomatic exchanges with Siam, as Thailand was called until 1939, and again between 1945 and 1949. However, it was during the later reigns of King Mongkut, and his son King Chulalongkorn, that Thailand established firm rapprochement with Western powers. It is a widely held view in Thailand that the diplomatic skills of these monarchs, combined with the modernising reforms of the Thai Government, made Siam the only country in South and Southeast Asia to avoid European colonisation. This is reflected in the country's modern name, Prathet Thai or Thai‐land, used since 1939 (although the name was reverted to Siam during 1945–49), in which prathet means "nation" and thai means "free".

The Anglo-Siamese Treaty of 1909 defined the modern border between Siam and British Malaya by securing Thai authority over the provinces of Pattani, Yala, Narathiwat and Satun, which were previously part of the semi‐independent Malay sultanates of Pattani and Kedah. A series of treaties with France fixed the country's current eastern border with Laos and Cambodia.

End of Absolute Monarchy and Military rule

The Siamese coup d'état of 1932 led by a group of young military and civil servants. The coup, usually called 'The Revolution of 1932', transformed the Government of Thailand from an absolute to a constitutional monarchy. The cabinet was presided by the prime minister. Military men always played a significant role in the politics even before 1932. In 1912, during the Rama VI reign, the arrest of young soldiers took place as a plot of coup urging the constitution and the change of the king's status was found.

King Rama VII, Prajadhipok initially accepted this change, granting the Constitution but later abdicated from his position due to disagreement with the government. The new, revolutionary government decided to install his ten year old nephew, Ananda Mahidol as the new monarch. Upon his abdication, King Prajadhipok said that the duty of a ruler was to reign for the good of the whole people, not for a selected few. Thai politics ran into turmoil as the revolutionary government plunged into factions; military and intellectuals. A coup and a rebellion took place. Eventually the military faction took control. The regime became evidently authoritarian under the prime minister Luang Phibulsongkram, one of the members of the Revolutionary military wing.

The young King Ananda Mahidol (Rama VIII) died in 1946 under somewhat mysterious circumstances, the official explanation being that he shot himself by accident while cleaning his gun. He was succeeded by his brother Bhumibol Adulyadej, the longest reigning king of Thailand, and very popular with the Thais. Although nominally a constitutional monarchy, Thailand was ruled by a series of military governments, most prominently led by Luang Phibunsongkhram and Sarit Dhanarajata, interspersed with brief periods of democracy.

In early January 1941, Thailand invaded French Indochina, beginning the French-Thai War. The Thais, better equipped and outnumbering the French forces, easily reclaimed Laos. The French decisively won the naval Battle of Koh Chang.

The Japanese mediated the conflict, and a general armistice was declared on January 28. On May 9 a peace treaty was signed in Tokyo, with the French being coerced by the Japanese into relinquishing their hold on the disputed territories.

On December 8, 1941, a few hours after the attack on Pearl Harbor, Japan demanded the right to move troops across Thailand to the Malayan frontier. Japan invaded the country and engaged the Thai army for six to eight hours before Phibunsongkhram ordered an armistice. Shortly thereafter Japan was granted free passage, and on December 21, 1941, Thailand and Japan signed a military alliance with a secret protocol wherein Tokyo agreed to help Thailand regain territories lost to the British and French (i.e. the Shan States of Burma, Malaya, Singapore, & part of Yunnan, plus Laos & Cambodia) Subsequently, Thailand undertook to 'assist' Japan in its war against the Allies. NOTE: Japan's distrust of Thailand extended to the point of rearming their 'Allies' with controlled munitions, including the famous Siamese Mauser, which was manufactured in an unusual caliber. It should be remembered that the Seri Thai operated freely, often with support from members of the Royal family (Prince Chula Chakrabongse) and members of the government and that the Thai Army was considered untrustworthy by the Japanese.

After Japan's defeat in 1945, with the help of a group of Thais known as Seri Thai who were supported by the United States, Thailand was treated as a defeated country by the British and French, although American support mitigated the Allied terms. Thailand was not occupied by the Allies, but it was forced to return the territory it had regained to the British and the French. In the postwar period Thailand had relations with the United States, which it saw as a protector from the communist revolutions in neighboring countries.

Communist guerillas existed in country from early '60s up to 1987, but never posed a serious threat to the state, but at the peak of movement they counted almost 12,000 full-time fighters.

Recently, Thailand also has been an active member in the regional Association of Southeast Asian Nations (ASEAN), especially after democratic rule was restored in 1992.

Democracy

Post-1973 has been marked by a struggle to define the political contours of the state. It was won by the King and General Prem Tinsulanonda, who favored a monarchy constitutional order.

The post-1973 years have seen a difficult and sometimes bloody transition from military to civilian rule, with several reversals along the way. The revolution of 1973 inaugurated a brief, unstable period of democracy, with military rule being reimposed after the 6 October 1976 Massacre. For most of the 1980s, Thailand was ruled by Prem, a democratically-inclined strongman who restored parliamentary politics. Thereafter the country remained a democracy apart from a brief period of military rule from 1991 to 1992. The populist Thai Rak Thai party, led by prime minister Thaksin Shinawatra, came to power in 2001. Yet his rule was under attack due to several charges; human right abuse, suppression of freedom press, conflict of interest, anti- monarchy, and corruption. In mid-2005, Sonthi Limthongkul, a well-know media tycoon, became the foremost Thaksin's critic. Eventually Sonthi and his alliances founded an opposition mass movement called 'the People's Alliance for Democracy (PAD), beginning its mass street protest.

On September 19, 2006, after the dissolution of the parliament, Thaksin then became the provisional government. While he was in New York for a meeting of the UN, Army Commander-in-Chief Lieutenant General Sonthi Boonyaratglin launched a bloodless coup d'état. A general election on 23 December 2007 restored a civilian government, led by Samak Sundaravej of the People Power Party, with close relation to Thaksin.

In mid-2008, the People's Alliance for Democracy (PAD) led large protests against the government of Prime Minister Samak Sundaravej, whom they criticized for his ties to former Prime Minister Thaksin Shinawatra. On 26 August, 2008, the protesters occupied several government ministries, including the Government House, to force the government to give in to demands. Beginning August 29, protesters disrupted air and rail infrastructure, including Suvarnabhumi airport.. The chaos ended in December when three of the parties that formed the government were dissolved by the Constitutional Court for serious election fraud. After this decision, many previous coalition partners of the government then defected and joined the main opposition party, the Democrat party, to form a new government.