Phra Bat Somdet Phra Chao Uthomphon Mahaphon Phinit () was the 32nd and penultimate monarch of the Ayutthaya Kingdom, ruling in 1758 for about two months. Facing various throne claimants, Uthumphon was finally forced to abdicate and enter monkhood. For his preference of being a monk to keep the throne, earned him the epithet "Khun Luang Ha Wat" (), or "the king who prefers the temple".
Prince Dok Duea or Prince Uthumphon—"Dok Duean" and "Uthmphon" are under the same meaning, "fig"—was a son of Borommakot. In 1746, his elder brother, Prince Thammathibet who had been appointed as the Front Palace, was beaten to death for his affair with one of Borommakot's concubines. Borommakot didn't appoint the new Front Palace as Kromm Khun Anurak Montri or Ekkathat, the next in succession line, was proved to be incompetent. In 1757, Borommakot finally decided to skip Anurak Montri altogether and made Uthumphon the Front Palace—becoming Kromma Khun Phon Phinit.

In 1758, upon the passing of Borommakot, Uthumphon was crowned. However, he faced oppositions from his three half-brothers, namely, Kromma Meun Chit Sunthon, Kromma Meun Sunthon Thep, and Kromma Meun Sep Phakdi. Uthumphon then reconciled with his half-brothers and took the throne peacefully.

Ekkathat, who had become a monk, decided to made himself a king only two months after Uthumphon's coronation. The three half-brothers resented and fought Ekkathat, and they were executed by Ekkathat. Uthumporn then gave up his throne to his brother and leave for the temple outside Ayutthaya so as to become a monk.

In 1760, Alaungpaya of Burma led his armies invading Ayutthaya. Uthumphon was asked to leave monkhood to fight against the Burmese. However, Alongpaya died during the campaigns and the invasion suspended. Uthumphon, once again, returned to monkhood.

The Burmese, however, came back in 1767 under the commission of Hsinbyushin and led by Neimyo Thihapate. Ayutthaya under Ekkathat was in turmoil, without authorities or powers to counter the Burmese invaders. Though he was strongly urged to take role in leading Siamese armies, Uthumphon chose to stay in the monk status. Ayutthaya finally fell. Uthumphon was captured by the Burmese forces and was brought to Burma along with a large number of Ayutthaya's people.

Uthumphon was grounded near Ava, along with other Ayutthaya ex-nobles, where he was forced by the Burmese to give them knowledge about the history and court customs of Ayutthaya—preserved in the Ayutthayan affidavit. Hsinbyushin built a village near Mandalay for Uthumphon and his Siamese people—who then became the Yodia people. In accordance with Burmese chronicles, Uthumphon, as a monk, died in 1796 in the village.

Category:Rulers of Ayutthaya

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