Short answers, pulled from the story.
The Ayutthaya Kingdom fell on the 7th of April 1767 when the Burmese breached the city walls and systematically destroyed the capital. This event marked the end of a four-century-old empire that had been recognized as one of the three great powers of Asia.
King Uthong founded the Ayutthaya Kingdom on the 4th of March 1351 by merging four distinct port polities along the Lower Chao Phraya Basin. He initially ruled over a network of vassal cities rather than a unified nation, maintaining authority through familial connections.
King Borommatrailokkanat implemented the Palatine Law of 1455 which established the Chatusadom system or Four Pillars to organize the court. This reform replaced the old Muang Look Luang arrangement with a hierarchy of governors appointed by the king and shifted the kingdom from a maritime focus to a hinterland state.
King Naresuan secured the independence of the Ayutthaya Kingdom by slaying the Burmese heir-apparent Mingyi Swa in a famous elephant duel in 1593. This victory followed his proclamation of independence in May 1584 and ended a period of Burmese domination.
The 1688 coup in the Ayutthaya Kingdom was caused by a religious and political crisis involving French Jesuits attempting to convert the royal family to Catholicism. Phetracha, the king's elephantry commander, led the coup to remove King Narai and his chief advisor Constantine Phaulkon, resulting in the expulsion of the French and English.
The Ayutthaya Kingdom collapsed in 1767 because it failed to adapt to the changing military landscape and could not withstand a prolonged siege by the Burmese Konbaung dynasty. The introduction of capitalism and the rise of commoners undermined the traditional labor control system that formed the military and government organization of the kingdom.