Thai people, who originally lived in southwestern China, migrated into mainland Southeast Asia over a period of many centuries. The oldest known mention of their existence in the region by the exonym Siamese is in a 12th-century A.D. inscription at the Khmer temple complex of Angkor Wat in Cambodia, which refers to syam, or "dark brown", people.[1] It was believed that Siam derived from the Sanskrit word syam, or "brown race", with a contemptuous signification. Sien in Chinese writings is the name for the northern kingdom that centered on Sukhothai and Sawankalok; but to the Siamese themselves, the name of the country has always been Mueang Thai.
The country's designation as Siam by Westerners likely came from the Portuguese, the first Europeans to give a coherent account of the country. Portuguese chronicles noted that the king of Sukhothai had sent an expedition to Malacca at the southern tip of the Malay Peninsula in 1455. Following their conquest of Malacca in 1511, the Portuguese sent a diplomatic mission to Ayutthaya. A century later, on 15 August 1612, The Globe, an East India Company merchantman bearing a letter from King James I, arrived in "the Road of Syam" "By the end of the 19th century, Siam had become so enshrined in geographical nomenclature that it was believed that by this name and no other would it continue to be known and styled."
Indianized kingdoms such as the Mon, Khmer and Malay kingdoms had ruled the region. Thai people established their own states starting with Sukhothai, Chiang Saen and Chiang Mai and 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