The sixteenth century witnessed the rise of Burma, which, under an aggressive dynasty, had overrun Chiang Mai and Laos and made war on the Thai. In 1569 Burmese forces, joined by Thai rebels mostly royal family members of Siam, captured the city of Ayutthaya and carried off the whole royal family to Burma. Dhammaraja (1569-90), a Thai governor who had aided the Burmese, was installed as vassal king at Ayutthaya. Thai independence was restored by his son, King Naresuan (1590- 1605), who turned on the Burmese and by 1600 had driven them from the country.
Determined to prevent another treason like his father's, Naresuan set about unifying the country's administration directly under the royal court at Ayutthaya. He ended the practice of nominating royal princes to govern Ayutthaya's provinces, assigning instead court officials who were expected to execute policies handed down by the king. Thereafter royal princes were confined to the capital. Their power struggles continued, but at court under the king's watchful eye.