Pinklao () (September 4, 1808 – January 7, 1866) was the viceroy of Siam. He was the younger brother of Mongkut, King Rama IV, who crowned him as a monarch with equal honor to himself. Early life Prince Chutamani was born on September 4, 1808, as a son of Prince Isarasundhorn and Princess Bunrod at the Phra Racha Wang Derm or Thonburi Palace. Prince Chutamani also had an elder brother—Prince Mongkut—who was seven years older. In 1809, Prince Isarasundhorn was crowned as Rama II and his mother became Queen Sri Suriyendra. They all moved to the Grand Palace. The government of Rama II, however, was dominated by Kromma Meun Jessadabodindra, his son with Sri Sulalai. In 1824, Mongkut became a monk according to Thai traditions. However, Rama II fell ill and died in the same year. The nobility, led by Chao Phraya Abhay Pudhorn, the Prime Minister, and Prayurawongse, the Minister of Foreign Affairs, supported Jessadabodindra for the throne as he proved competent to rule. Jessadabodindra was crowned as Rama III. Prince Mongkut then stayed in his monkhood to avoid political intrigues. Prince Chutamani, however, entered the government under Nangklao and was awarded the title "Kromma Khun Isaret-rangsant". Kromma Khun Isaret moved to the Thonburi Palace, where he lived with his mother Queen Sri Suriyendra until her death in 1836. The young prince was, as was his elder brother, well disposed towards foreigners. In 1833 at age 25 and known to diplomatist Edmund Roberts as Chow-Phoi-Noi or Mom-fa-Noi, the prince secretly visited the mission house during Roberts' negotiations for the Siamese–American Treaty of Amity and Commerce, the United States' first treaty with Thailand. The prince was pleased and gratified with a nighttime visit to the man-of-war Peacock, during which the men mustered to quarters for naval exercises. Roberts stated that the prince spoke and wrote the English language with considerable fluency, and his pronunciation was correct. Reign with Mongkut Nangklao died in 1851. Kromma Khun Isaret was at the time the heir presumptive to the throne, but the return and claim of his brother Prince Mongkut was stronger. Mongkut was then crowned on May 25, 1851, with the support of the nobility. Concurrently Prince Isaret was crowned as Uparaja Pinklao with equal honor to Mongkut. In practice, Pinklao held the title of Lord of the Front Palace. The popular legend holds that Mongkut's own astrological calculations stated that his brother