Buddha Yodfa Chulaloke or Phutthayotfa, posthumously titled Rama I the Great, was King of Siam (now called Thailand) from 1782 to 1809, and the founder of the Chakri dynasty which rules Thailand to this day.

The future king was born on March 20, 1737 in Ayutthaya, his birth name was Thong Duang. He was born the son of Phra Aksorn Sundara Smiantra, a noble of the kingdom of Ayutthaya, whom following the fall of Ayutthaya became Chao Phya Chakri at Pitsanuloke. After receiving his education in a Buddhist temple, his father sent him to become a squire for king Uthumphon, and it was at this moment that he met his friend Tak Sin, who would become King Taksin, Rama's future predecessor. After the fall of Ayutthaya, he rejoined the ranks of king Taksin under the name Chao Phraya Chakri. He was given the name Buddha Yodfa Chulaloke posthumously by king Rama III, Nangklao.