[clarification needed] Upon King Prasat Thong’s death in 1655, Chaofa Chai, his eldest son, succeeded his father as King Sanpet VI.
However, it was a Thai tradition gave brothers a higher priority over sons in succession.
After nine months of ascension, Chaofa Chai was executed following a coup.
[1]: 216–217 [2]: 56 Narai and his uncle marched[3] into the palace, and Si Suthammaracha crowned himself king.
Si Suthammaracha appointed Narai as the Uparaja, or the Front Palace.