Phrabat Somdet Phra Pinklao Chaoyuhua () (September 4, 1808 - January 7, 1866) was the younger brother and the Vice-King of King Mongkut (Rama IV) of Siam, 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 Old Thonburi Palace. Prince Chutamani also had an elder brother - Prince Mongkut - who was seven years older. In 1809, Prince Isarasundhorn was crowned as Buddha Loetla Nabhalai and his mother became Queen Sri Suriyendra. They all moved to the Grand Palace.

The government of Buddha Loetla Nabhalai, however, was dominated by Krom Meun Jessadabodindra - Buddha Loetla Nabhalai's son with Concubine Riam. In 1824, Prince Mongkut became a monk according to Siamese traditions. However, Buddha Loetla Nabhalai fell ill and died in the same year. The nobility, led by Chao Phraya Abhay Pudhorn the Samuha Nayok and Dis Bunnak the minister of Krom Tha supported Prince Jessadabodindra for the throne as he was proved to be very competent to rule. Therefore, Jessadabodindra was crowned.

Prince Mongkut then stayed in his monkhood to avoid political intrigues. Prince Chutamani, however, entered the government under Jessadabodindra and was awarded the title Krom Khun Isaret Rangsan. Krom Khun Isaret moved to the Old Palace in Thonburi, where he lived with his mother Queen Sri Suriyendra until her death in 1836.

Reign with Mongkut

Jessadabodindra died in 1851. Krom 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 , and on May 25, 1851 with the support of the nobility. Concurrently Prince Isaret was crowned as the Vice King Pinklao with equal honor to Mongkut. In practice, Pinklao held the title of Front Palace. The popular legend holds that Mongkut's own astrological calculations stated that his brother Prince Isaret also holds the fate to become a king. As a result he gave Pinklao the same styles and title normally reserved for a King such as Phrabat Somdet and Chao Yu Hua: Phrabat Somdet Phra Pinklao Chao Yu Hua. David Wyatt considers his appointment a way of Mongkut’s to prevent Pinklao from challenging his own position. Nevertheless, the relationship between the brothers remained peaceful and good throughout Mongkut's reign.

The government under Mongkut was however, in the strong hands of Somdet Chao Phraya Borom Maha Prayurawongse and Somdet Chao Phraya Borom Maha Pichaiyat, the former as Chief Minister of Siam. Interference from both King and Vice King was therefore minimal. Expanding his interests to foreign affairs Pinklao, who was known for his fluency in the English language was able to respond to the letters of John Bowring. In the letters, he referred himself as the Second king and his brother as the First king. As a result Pinklao was able to play a great role in the negotiation of the Bowring Treaty.

As the second monarch and Front Palace, Pinklao maintained his own private army and a navy of several modern ships. It was during this time that the power of the Front Palace greatly expanded. Apart form state affairs, Pinklao was interested in both western and Lao culture, speaking English, drilling his troops in European fashion, singing, dancing, and playing the khene to mor lam music.

Pinklao died on January 7, 1866, predeceasing his brother for two years. His nephew the 15 year old Chulalongkorn (son of Mongkut), succeeded to the throne in 1868 and Somdet Chao Phraya Borom Maha Sri Suriyawongse (the Regent) arranged the title of Front Palace to be succeeded by Pinklao's son with Princess Aim, Prince Yingyot later Vichaichan.