Mongkut (died 1868)

King of Siam (Thailand) from 1851, known later as Rama IV. During his reign the country was opened to foreign trade by the Bowring Treaty of 1855 between Siam and England, marking the beginning of Siam's effective diplomatic response to European imperalism. Although he later acquired the reputation of a reformer, Mongkut was in reality an enlightened traditional ruler with an open mind towards Western learning.

As a young man, Mongkut's claim to the throne on the death of Rama II in 1824 was overlooked, and he spent the reign of his half-brother Rama III (1824–51) as a monk in Buddhist monasteries. He became a scholar of both Pali and Western languages, with Christian missionaries as his teachers, and as a result he developed a strong desire to reform the Buddhist priesthood in Thailand. He created a reformed sect known as the Thammayut branch of the priesthood. In 1851 he was finally allowed to succeed to the throne as the candidate of a court faction favouring improved relations with the West.