The Kingdom of Thailand (ราชอาณาจักรไทย) is a sovereign state in southeastern Asia. It borders Burma, Laos, Cambodia, and Malaysia.
Similar to other regions in Southeast Asia, Thailand was heavily influenced by Indian culture, starting with the Kingdom of Funan from around the 1st century CE to the Khmer Empire. Thailand was one of these states; it was mostly brought indirectly through the Indianized kingdoms of Dvarati, Srivijaya, and Cambodia. Later Thailand was influenced by the south Indian Pallava dynasty and north Indian Gupta Empire. In 1257, the Mongols attempted to invade Thailand, though like their attempts of conquering the other states of Indochina, this was unsuccessful. After the fall of the Khmer Empire in the 13th century, various states thrived there, established by the various Tai peoples, Mons, Khmers, Chams and Ethnic Malays, as seen through the numerous archaeological sites and artefacts that are scattered throughout the Siamese landscape. The first Thai state is traditionally considered to be the Buddhist Sukhothai Kingdom, which was founded in 1238. Ayutthaya, the second Thai state, became one of the most vibrant trading centers in Asia. European traders arrived in the 16th century, beginning with the Portuguese. Despite massive pressure from European empires, Thailand has never been colonized. As a result, the country became a buffer state between parts of Southeast Asia that were colonized by the two colonial powers, Great Britain and France. . Western influence nevertheless led to many reforms in the 19th century and major concessions.
During the Pacific War, Japan demanded a right to move through Thailand, resulting in a swift invasion on December 8, 1941. This engaged the Royal Thai Army for six to eight hours before Plaek Phibunsongkhram ordered an armistice. This gave Japan the ability to move through Thailand, and would lead to the creation of the Japanese puppet state, the State of Thailand.
Subsequently, Thailand declared war on the United Kingdom and China, in order to "assist" their Japanese masters. Approximately 300,000 Asian laborers and 60,000 Allied prisoners of war (POWs) worked on the Burma Railway, which is commonly known as the "Death Railway". After the Indochina War, the State of Thailand was abolished, returning Thailand to its original state. Thailand then went through decades of political instability characterised by a number of coups d'état, as one military regime replaced another, but eventually progressed towards a stable, prosperous democracy in the 1980s.