The Ayutthaya kings adopted Khmer cultural influences from the very beginning. No longer the paternal and accessible rulers that the kings of Sukhothai had been, Ayutthaya's sovereigns were absolute monarchs and assumed the title devaraja (god-king). The early part of this period saw Ayutthaya extend its sovereignty over neighboring Thai principalities and come into conflict with its neighbors. During the 17th century, Siam started diplomatic and commercial relations with western countries. In 1767, after repeated attempts, the Burmese invaded and successfully captured Ayutthaya.
Despite their overwhelming victory, the Burmese did not retain control of Siam for long. A young general named Phya Taksin and his followers broke through the Burmese lines and escaped to Chantaburi. Seven months after the fall of Ayutthaya, he and his forces sailed back up the Chao Phraya River to Ayutthaya and expelled the Burmese occupation garrison, though tragically the capital had been looted and nearly razed.