Various Indianised kingdoms such as the Mon, the Khmer Empire and Malay states ruled the region, competing with Thai states such as Ngoenyang, the Sukhothai Kingdom, Lan Na and the Ayutthaya Kingdom, which rivaled each other.
European contact began in 1511 with a Portuguese diplomatic mission to Ayutthaya, one of the great powers in the region.
Apart from a brief period of parliamentary democracy in the mid 1970s, Thailand has periodically alternated between democracy and military rule.
In the 21st century, Thailand endured a political crisis that culminated in two coups and the establishment of its current and 20th constitution by the military junta.
The word Śyâma is possibly not its origin, but a learned and artificial distortion.
Another theory is the name derives from Chinese: "Ayutthaya emerged as a dominant centre in the late fourteenth century.
According to French historian George Cœdès, "The Thai first enter history of Farther India in the eleventh century with the mention of Syam slaves or prisoners of war in" Champa epigraphy, and "in the twelfth century, the bas-reliefs of Angkor Wat" where "a group of warriors" are described as Syam.
Tai people started inhabiting in present-day Thailand in the 11th century, where Mon and Khmer kingdoms were situated at the time.According to George Cœdès, the word Thai (ไทย) means "free man" in the Thai language, "differentiating the Thai from the natives encompassed in Thai society as serfs".) means "kingdom of Thailand" or "kingdom of Thai".Etymologically, its components are: ratcha (Sanskrit राजन्, rājan, "king, royal, realm") ; -ana- (Pali āṇā "authority, command, power", itself from the Sanskrit आज्ञा, ājñā, of the same meaning) -chak (from Sanskrit चक्र cakra- "wheel", a symbol of power and rule).However, a century later, the power of Sukhothai was overshadowed by the new Kingdom of Ayutthaya, established in the mid-14th century in the lower Chao Phraya River or Menam area.According to the most widely accepted version of its origin, Ayutthaya Kingdom rose from the earlier, nearby Lavo Kingdom and Suvarnabhumi with Uthong as its first king.
Following a bloodless revolution in 1932, Siam became a constitutional monarchy and changed its official name to "Thailand".