In 1767, Ayutthaya was facing the full blast of the Burmese siege. After being surrounded for 1 year and 2 months, Ayutthaya was defeated in the reign of King Ekathat, the last king of Ayutthaya.
After the sacking of Ayutthaya, the country had fallen apart. Many rulers proclaimed themselves independent.
Phraya Vajiraprakrn had prepared his army for 3 months before sailing up the Chao Phraya River and successfully seized Thonburi. He executed Thong-in, Thai governor whom the Burmese had placed over it. He later launched boldly attacking the main Burmese camp at Phosamton causing the death of General Suki. The Burmese were defeated and expelled from Ayutthaya in 1767 within 7 month of the destruction of Ayutthaya.