Mongkut (มงกุฎ crown[6]) was the second son of Prince Isarasundhorn, son of Phutthayotfa Chulalok, the first Chakri king of Siam (King Rama I) and Princess Bunreod. Mongkut was born in the Old (Thonburi) Palace in 1804, where the first son had died shortly after birth in 1801; joined by Prince Chutamani (เจ้าฟ้าจุฑามณี) in 1808.