the bas-reliefs at the Bayon and Angkor Wat, Zhou's journal is the most important source of information about everyday life at Angkor. Filled with vivid anecdotes and sometimes incredulous observations of a civilization that struck Zhou as colorful and exotic, it is an entertaining travel memoir as well.
End of the Angkorian period
The end of the Angkorian period is generally set as 1431, the year Angkor was sacked and looted by Ayutthaya invaders, though the civilization already had been in decline in the 13th and 14th centuries. During the course of the 15th century, nearly all of Angkor was abandoned, except for Angkor Wat, which remained a Buddhist shrine. Several theories have been advanced to account for the decline and abandonment of Angkor:
War with the Ayutthaya Kingdom
It is widely believed that the abandonment of the Khmer capital occurred as a result of Ayutthaya invasions. Ongoing wars with the Siamese were already sapping the strength of Angkor at the time of Zhou Daguan toward the end of the 13th century. In his memoirs, Zhou reported that the country had been completely devastated by such a war, in which the entire population had been obligated to participate. After the collapse of Angkor in 1431, many persons, texts and institutions were taken to the Ayutthaya capital of Ayutthaya in the west, while others departed for the new center of Khmer society at Longvek further south, though the official capital later moved, first to Oudong around 45 kilometres (28 mi) from Phnom Penh in PonheaLeu District, and then to the present site of Phnom Penh.
Erosion of the state religion
Some scholars have connected the decline of Angkor with the conversion of Cambodia to Theravada Buddhism following the reign of Jayavarman
