There is evidence of human habitation in Thailand that has been dated at 40,000 years before the present. 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.
After the fall of the Khmer Empire in the 13th century, various states thrived there, such as the various Tai, Mon, Khmer and Malay kingdoms, as seen through the numerous archaeological sites and artifacts that are scattered throughout the Siamese landscape. Prior to the 12th century however, the first Thai or Siamese state is traditionally considered to be the Buddhist kingdom of Sukhothai, which was founded in 1238.
The ruins of Wat Chaiwatthanaram at Ayutthaya. The city was burned and sacked in 1767 by a Burmese army under the King Hsinbyushin.
Following the decline and fall of the Khmer empire in the 13th–15th century, the Buddhist Tai kingdoms of Sukhothai, Lanna and Lan Xang (now Laos) were on the ascension. 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.
Ayutthaya's expansion centred along the Menam while in the northern valley the Lanna Kingdom and other small Tai city-states ruled the area. In 1431, the Khmer abandoned Angkor after the Ayutthaya forces invaded the city. 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. European traders arrived in the 16th century, beginning with the Portuguese, followed by the French, Dutch and English.
After the fall of Ayutthaya in 1767 to the Burmese, King Taksin the Great moved the capital of Thailand to Thonburi for approximately 15 years. The current Rattanakosin era of Thai history began in