CHETTHATHIRAT.

King Chetthathirat (c. 1613 - 1629, full Thai title: สมเด็จพระเชษฐาธิราช; RTGS: Somdet Phra Chetthathirat) was the eldest son of King Song Tham and older brother of King Athittayawong, all three of the House of Sukhothai. In childhood he was known as Chetthakuman (พระเชษฐากุมาร), meaning 'Chettha the Infant', or simply Chettha. He reigned for a period of eight months from 1628-1630.
When his father King Song Tham died there was a scramble for the crown between Prince Chettha and his younger brother Prince Si Sin (พระศรีศิลป์). On Chettha's side were Ok-ya Si Worawong and Ok-ya Senaphimuk is a title above Khun) who were influential enough to capture Si Sin and have him executed. After doing just this, they then informed Chettha of the deed and he ascended the throne as His Majesty King Chetthathirat or His Majesty King Borommarachathirat II (สมเด็จพระบรมราชาธิราชที่ ๒; Somdet Phra Borommarachathirat thi Song); he was fifteen years old at the time. Ok-ya Si Worawong was then also promoted to the title of Chao Phraya Kalahom Suriyawong (เจ้าพระยากลาโหมสุริยวงศ์).
After reigning for eight months he became suspicious of Chao Phraya Kalahom Suriyawong's ambition to take the crown for himself and plotted out a way to get rid of him. This was discovered by Chao Phraya Kalahom Suriyawong before it could be realised however, and the latter thus launched an attack on the residential palace with King Chetthathirat fleeing rather than countering the attack. Chao Phraya Kalahom Suriyawong dispatched two figures, the Phraya Decho (เดโช) and Phraya Thai Nam (ท้ายน้ำ) to follow suit immediately and capture Chetthathirat in the Mok Noi Forests (ป่าโมกน้อย; Pa Mok Noi), where Chetthathirat was subsequently caught and killed.