Thailand retained a tradition of trade with its neighbouring states, from China to India, Persia, and Arab lands.
Ayutthaya became one of the most vibrant trading centres in Asia.
According to the Encyclopædia Britannica, "A quarter to a third of the population of some areas of Thailand and Burma were slaves in the 17th through the 19th centuries." This has been ascribed to the long succession of able rulers in the past four centuries who exploited the rivalry and tension between the French and British Empire.
In 1896, Britain and France guaranteed of the Chao Phraya valley as their buffer state (not the whole of Siam), while the remaining parts of Southeast Asia were colonized by the western powers.
Thailand was renamed to Siam from 1946 to 1948, after which it again reverted to Thailand.
Similar to other regions in Southeast Asia, Thailand was heavily influenced by the culture and religions of India, starting with the Kingdom of Funan around the 1st century CE to the Khmer Empire.
Indian influence on Thai culture was partly the result of direct contact with Indian settlers, but mainly it was brought about indirectly via the indianized kingdoms of Dvaravati, Srivijaya, and Cambodia.
According to 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.
Additionally, "the Mongols, after the seizure of Ta-li on January 7, 1253 and the pacification of Yunnan in 1257, did not look with disfavor on the creation of a series of Thai principalities at the expense of the old Indianized kingdoms." The Menam Basin was originally populated by the Mons, and the location of Dvaravati in the 7th century, followed by the Khmer Empire in the 11th.