KING PRASAT THONG.

King Prasat Thong (Thai: สมเด็จพระเจ้าปราสาททอง) (reigned 1629-1656) was the first king of Prasat Thong dynasty, the 4th dynasty of Ayutthaya kingdom. He was the Defense minister (ออกญากลาโหม) of King Songtham.
It is said that Prasat Thong was a secret son of King Ekathotsarot and a villager. He came to power by a coup, murdering a young king. Jeremias Van Vliet's History of Siam tells his story in great details. He was known as an able leader but also brutal. As he rose by violence, he then crushed any suspects who could be a threat. Many officials and even some royal relatives of previous reign were arrested and executed with high treason charge.
As a powerful and decisive leader, he promulgated many criminal laws and sometimes, according to Van Vliet, he even executed prisoners by himself.
Siam was a major trading center attracting Europeans merchants. Prasat Thong was interested in controlling the towns in the southern peninsular, perhaps, because of profits from oversea trade. Ayutthaya lost northern subjugated principalities such as Chiangmai.
His son, Narai, eventually began a significant relationship with European countries