Wikipedia
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 18041 October 1868), was the fourth monarch of Siam (Thailand) under the House of Chakri, ruling from 1851 to 1868.
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 Siamin turn based on a 1944 novel by an American missionary about Anna Leonowens' years at his court, from 1862 to 1867.
During his reign, the pressure of Western expansionism was felt for the first time in Siam. Mongkut embraced Western innovations and initiated the modernization of his country, both in technology and culture—earning him the nickname "The Father of Science and Technology" in Siam.
Mongkut was also known for his appointing his brother, Prince Chutamani, as Second King, crowned in 1851 as King Pinklao. Mongkut himself assured the country that Pinklao should be respected with equal honor to himself (as King Naresuan had done with his brother Ekathotsarot in 1583). Mongkut's reign was also the time when the power of the House of Bunnag reached its zenith and became the most powerful noble family of Siam.