In 1511 Ayutthaya received a diplomatic mission from the Portuguese, who earlier that year had conquered Malacca. These were probably the first Europeans to visit the country. Five years after that initial contact, Ayutthaya and Portugal concluded a treaty granting the Portuguese permission to trade in the kingdom. A similar treaty in 1592 gave the Dutch a privileged position in the rice trade.

Foreigners were cordially welcomed at the court of Narai (1657-88), a ruler with a cosmopolitan outlook who was nonetheless wary of outside influence. Important commercial ties were forged with Japan. Dutch and English trading companies were allowed to establish factories, and Thai diplomatic missions were sent to Paris and The Hague. By maintaining all these ties, the Thai court skillfully played off the Dutch against the English and the French against the Dutch in order to avoid the excessive influence of a single power.

In 1664, however, the Dutch used force to exact a treaty granting them extraterritorial rights as well as freer access to trade. At the urging of his foreign minister, the Greek adventurer Constantine Phaulkon, Narai turned to France for assistance. French engineers constructed fortifications for the Thai and built a new palace at Lop Buri for Narai. In addition, French missionaries engaged in education and medicine and brought the first printing press into the country. Louis XIV's personal interest was aroused by reports from missionaries suggesting that Narai might be converted to Christianity.

The French presence encouraged by Phaulkon, however, stirred the resentment and suspicions of the Thai nobles and Buddhist clergy. When word spread that Narai was dying, a general, Phra Phetracha, killed the designated heir, a Christian, and had Phaulkon put to death along with a number of missionaries. The arrival of English warships provoked a massacre of more Europeans. Phetracha (reigned 1688-93) seized the throne, expelled the remaining foreigners, and ushered in a 150-year period during which the Thai consciously isolated themselves from contacts with the West.

Data as of September 1987