Thammathibet Chaiyachet Suriyawong, the Prince Senaphithak (Thai: สมเด็จเจ้าฟ้าธรรมธิเบศรไชยเชษฐสุริยวงศ กรมขุนเสนาพิทักษ์) or Prince Narathibet (Thai: นราธิเบศร์), also known as Prince Kung/ Chao Fa Kung (Thai: เจ้าฟ้ากุ้ง; 1715 – 1755^[1]), was Viceroy of the front palace of the Kingdom of Ayutthaya, from 1732/33^{[citation needed]} but he is more well-known as one of the most prominent poets in Thai literature. He also created the music for the Royal Barge Procession.

Thammathibet, Prince Senaphithak was the eldest son of King Borommakot (reg. 1733 to 1758) and Princess Aphainuchit or Phra Phan Watsa Yai.

In his poetic works praised for their lyrical language, Thammathibet describes the beauty of the Royal Barge procession, illustrating the work of the rowers, the individual boats, and the sight of the entire procession fleet. Nature, both plant and animal life, are also themes of his poetry. He often deals with the beauty of women, a subject which eventually led to disaster in real life.

Thammathibet and his half-brother Chao Sakaeo (Prince Sunthon Thep) had an argument about an elephant. In April, 1746, Thammathibet reportedly laid siege to the palace of his half-brother, forbidding any entrance or exit. Nevertheless, Chao Sakaeo and his sons were able to enter the palace of the king and lodge complaints there. The King was surprised by these clashes. Thammathibet also hurried to the royal palace but he was not allowed to enter, so he returned to his own palace.

Later, he was brought before his father, who asked him the reason for his presumptuous behavior. Thammathibet remained silent, which rankled the King, who left his son in jail. Thammathibet was chained in a single cell, and no one was allowed to join him. Meanwhile, the accusations against him increased. King Borommakot entrusted Chao Sakaeo and Chao Krommun Poon (Prince Chitsunthorn), along with Okya Chakri (Chancellor) and the Phraklang, with the prisoner's interrogation, which did not bode well. Thammathibet did not speak, and was twice punished with twenty blows, then his soles were burnt.

His most important advisers were also imprisoned and "questioned". They made many accusations: Thammathibet had made copies of the keys to the chambers of the king, the queen, and the royal concubines, so that he could get access to the rooms by night. In addition, his followers had bought and hidden weapons to use at the right moment. And finally, they confessed that Thammathibet was responsible for the death of several monks and the mutilation of some of his subordinates. Thereupon the king ordered fifty blows.

During the further interrogations, Thammathibet confessed that he had visited four of the numerous royal concubines and planned to assassinate his father the king and his family and seize power in Ayutthaya. The king gave an order to give Thammathibet fifty more blows and burn his forehead, arms, and legs. In the course of this torture, Thammathibet, the four concubines, and some higher counselors of the prince died.

Prince Thammathibet was cremated in Wat Chaiwatthanaram in Ayutthaya along with Chao Fa Nim, his father's first concubine, and Chao Sangwan, according to Buddhist rite.

• He Kaki Sam Ton (Thai: บทเห่เรื่องกากี 3 ตอน)
• He Sangwat (Thai: บทเห่สังวาส)
• He Khruan Yang La Bot (Thai: เห่ครวญอย่างละบท)
• Kap Ho Khlong (Thai: กาพย์ห่อโคลง)
• Nirat Than Sok (Thai: นิราศธารโศก)
• Nirat Than Thongdaeng (Thai: นิราศธารทองแดง)
• Lilit Nanthopananthasut Kham Luang (Thai: นันโทปนันทสูตรคำหลวง)
• Lilit Phra Malai Kham Luang (Thai: พระมาลัยคำหลวง)

• Bhawan Ruangslip: Dutch East India Company Merchants at the Court of Ayutthaya: Dutch Perception of the Thai Kingdom, c. 1604-1765. Leiden: Brill 2007. ISBN 978-9004156005.
• Thammathibet, Prince (2016). "On Lovemaking" (PDF). Journal of the Siam Society. 104. Translated by Baker, Chris; Pasuk Phongpaichit: 293–294. ISSN 0304-226X.