Stone Wheel of Law, Dvaravati Period (sixth-ninth centuries AD), found at Phra Pathom Chedi, Nakhon Pathom Province.

LITTLE IS KNOWN of the earliest inhabitants of what is now Thailand, but 5,000-year-old archaeological sites in the northeastern part of the country are believed to contain the oldest evidence of rice cultivation and bronze casting in Asia and perhaps in the world. In early historical times, a succession of tribal groups controlled what is now Thailand. The Mon and Khmer peoples established powerful kingdoms that included large areas of the country. They absorbed from contact with South Asian peoples religious, social, political, and cultural ideas and institutions that later influenced the development of Thailand's culture and national identity.

The Tai, a people who originally lived in southwestern China, migrated into mainland Southeast Asia over a period of many centuries. The first mention of their existence in the region is a twelfth-century A.D. inscription at the Khmer temple complex of Angkor Wat in Cambodia, which refers to syam, or "dark brown" people (the origin of the term Siam) as vassals of the Khmer monarch. In 1238 a Tai chieftain declared his independence from the Khmer and established a kingdom at Sukhothai in the broad valley of the Mae Nam (river) Chao Phraya, at the center of modern Thailand. Sukhothai was succeeded in the fourteenth century by the kingdom of Ayutthaya. The Burmese invaded Ayutthaya and in 1767 destroyed the capital, but two national heroes, Taksin and Chakkri, soon expelled the invaders and reunified the country under the Chakkri Dynasty.

Over the centuries Thai national identity evolved around a common language and religion and the institution of the monarchy. Although the inhabitants of Thailand are a mixture of Tai, Mon, Khmer, and other ethnic groups, most speak a language of the Tai family. A Tai language alphabet, based on Indian and Khmer scripts, developed early in the fourteenth century. Later in the century a famous monarch, Ramathibodi, made Theravada Buddhism the official religion of his kingdom, and Buddhism continued into the twentieth century as a dominant factor in the nation's social, cultural, and political life. Finally, the monarchy, buttressed ideologically by Hindu and Buddhist mythology, was a focus for popular loyalties for more than seven centuries. In the late twentieth century the monarchy remained central to national unity.

During the nineteenth century, European expansionism, rather than Thailand's traditional enemies, posed the greatest threat to the kingdom's survival. Thai success in preserving the country's independence (it was the only Southeast Asian country to do so) was in part a result of the desire of Britain and France for a stable buffer state separating their dominions in Burma, Malaya, and Indochina. More important, however, was the willingness of Thailand's monarchs, Mongkut (Rama IV, 1851-68) and Chulalongkorn (Rama V, 1868-1910), to negotiate openly with the European powers and to adopt European-style reforms that modernized the country and won it sovereign status among the world's nations. Thailand (then known as Siam) paid a high price for its independence, however: loss of suzerainty over Cambodia and Laos to France and cession of the northern states of the Malay Peninsula to Britain. By 1910 the area under Thai control was a fraction of what it had been a century earlier.

In the early decades of the twentieth century, Thailand's political system, armed forces, schools, and economy underwent drastic changes. Many Thai studied overseas, and a small, Western-educated elite with less traditional ideas emerged. In 1932 a bloodless coup d'etat by military officers and civil servants ended the absolute monarchy and inaugurated Thailand's constitutional era. Progress toward a stable, democratic political system since that time, however, has been erratic. Politics has been dominated by rival military-bureaucratic cliques headed by powerful generals. These cliques have initiated repeated coups d'etat and have imposed prolonged periods of martial law. Parliamentary institutions, as defined by Thailand's fourteen constitutions between 1932 and 1987, and competition among civilian politicians have generally been facades for military governments.

Data as of September 1987