| The earliest kingdom of Thailand was the Sukhothai | | | | Pho Khun Ramkhamhaeng took over the throne. |
| Kingdom, built around the city of Sukhothai. Sukhothai | | | | During his regime, Sukhothai enjoyed a golden time and |
| was the capital of Siam, and is located in north central | | | | prospered to its maximum. |
| Thailand. This was the earliest kingdom and it existed | | | | Ramkhamhaeng introduced the first Thai letters. During |
| between 13th and 14th century. | | | | his regime, the kingdom expanded and spread over a |
| In the 13th century, Sukhothai was a part of Khmer | | | | large area from Martaban (now Myanmar) to Luang |
| empire. It was recognized as a Thai ruled kingdom | | | | Prabang (present day Laos) and down to the Malay |
| when two Thai chieftans, Pho Khun Pha Muang and | | | | Peninsula. The kingdom was larger than modern day |
| Pho Khun Bang Klang Hao, declared their individual | | | | Thailand. |
| independent kingdom in Thailand. The first king of | | | | Loethai, the son of Ramkhamhaeng, took over |
| Sukhothai was Pho Khun Bang Klang Hao who also | | | | Sukhothai after his father died. But he could not bring |
| called himself Pho Khun Si Indrathit or Intradit. | | | | the same prosperity to his kingdom as his father. Soon, |
| The kingdom of Sukhothai eventually expanded and | | | | other dependent Thai kings started liberating |
| made alliances with other Thai kingdoms. Their | | | | themselves from King Loethai. The once great |
| adopted Theravada Buddhism as their state religion. | | | | Kingdom of Sukhothai quickly became a small local |
| The son of the king Pho Khun Bang Klang Hao | | | | province and very soon lost its importance in the |
| succeeded the throne after him. Later on, his brother | | | | region. |