Phra Phutthayotfa Chulalok also known as Rama I (20 March 1737 – 7 September 1809), was the founder and the first monarch of the reigning House of Chakri of Siam (now Thailand).
He ascended the throne in 1782, after defeating a rebellion which had deposed King Taksin of Thonburi. He was also celebrated as the founder of Rattanakosin (now Bangkok) as the new capital of the reunited kingdom.
Rama I was born from a Mon family where his father served in the royal court in the Kingdom of Ayutthaya, and had served King Taksin in wars against the Burmese Konbaung dynasty and helped him in the reunification of Siam. During this time he emerged as Siam’s most powerful military leader. Thongduang was the first Somdet Chao Phraya, the highest rank the nobility could attain, equal to that of royalty. In 1782, he took control of Siam and crowned himself as the monarch. The most famous event in his reign was the Burmese-Siamese War of 1785, which was the last major Burmese assault on Siam.