Phrabat Somdet Phra Borommaracha Thirat IV () or Phrabat Somdet Phra Borommaracha Thirat Nor Buddhankoon () , formerly Prince Atitayawongse, was the short-reigning king of Ayutthaya from 1529 to 1533. Prince Atitayawongse was the son of Ramathibodi II and became the Uparaja in 1515. Following his father's death, Atitayawongse succeeded the Ayutthayan throne as Boromaracha IV. He appointed his brother, Prince Chairachathirat, as the Uparaja at Pitsanulok. Borommaracha IV died abruptly in 1533 due to an epidemic, leaving the throne to his five-year-old son, Prince Ratsadathirat.

Category:Year of birth missingCategory:1533 deathsCategory:Thai monarchsCategory:Rulers of Ayutthaya

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