Phra Bat Somdet Phra Poramenthra Maha Mongkut Phra Chom Klao Chao Yu Hua or Rama IV, known in English-speaking countries as King Mongkut (18 October 1804 – 1 October 1868), was the fourth monarch of Siam (Thailand) under the House of Chakri, ruling from 1851 to 1868. He was one of the most revered monarchs of the country.
Outside of Thailand, he is best known as the King in the 1951 musical and 1956 film The King and I, based on the 1946 film Anna and the King of Siam – in turn based on a 1944 novel by an American missionary about Anna Leonowens' years at his court, from 1862 to 1867.