There were a lit of wars between various Burmese armies and Ayutthaya. The first large war started in 1539 A.D. It was known as the "chiang Kran War". The Burmese had successfully invaded the North of
Thailand and captured Chiang mai. This was the period of history which you can see in the Thai movie "The Legend of Suryothai". In 1549 Queen Suryothai and her daughter led a successful attack against the Burmese who were threatening the city of Ayutthaya. Two other wars caused the temporary defeat of the armies of Ayutthaya and the capture of the city. The first war was in 1569 A.D. and the second in 1767 A.D. However, on both occasions the armies of Ayutthaya took back the Kingdom and drove the Burmese out of Siam.
During the reign of King Mahindrathira there wa one infamous traitor called Phya Chakri. He was completely trusted by the King but secretly worked against him. He became the "enemy within