Before 1939, the country of Thailand was known as Siam.
While life on this land dates back nearly 20,000 years, it wasn’t until the the early 1200s that Siam began gaining a reputation as a strong cultural and political nation creating their first capital. The term Siam; actually refers to four different kingdoms, each with a different capital city; the Sukhothai Kingdom, the Ayutthaya Kingdom, the Thonburi Kingdom, and the Rattanakosin Kingdom.
Siam became Thailand in 1939, seven years after an uprising ended the absolute rule of the monarchy. Thailand then became a constitutional monarchy. The people of Thailand have an elected government, including a parliament, as well as a king.
Siam is unique among Southeast Asian nations in that it was never colonized by European forces. If you trace Thailand of today back to the beginning of the Sukhothai Kingdom, this small kingdom has been in existence for nearly 800 years.