Jayavarman VII (r. 1181–1218) is considered the most influential of the Khmer kings, bringing the Angkor Empire to its peak of power and territorial reach, but also perhaps signaling its eventual overreach. He assumed the throne later in life, following a turbulent period marked by two Cham invasions—one by land in 1177 and another by sea in 1178, during which Angkor itself was sacked. In 1181, after successfully driving out the Cham, Jayavarman was crowned king and undertook efforts to stabilize and reorganize the empire, centralizing power and initiating numerous public works projects.

Jayavarman’s initiatives were vast, including the construction of new roads and over a hundred hospitals, which employed up to 80,000 people. Ironically, the financial burden of such large-scale projects may have strained the resources of the populace, leading to hardship for many. Jayavarman also initiated a remarkable building campaign, commissioning temples like Ta Som, Preah Khan, Banteay Chhmar, Neak Pean, and the iconic Bayon. Notably, Jayavarman embraced Mahayana Buddhism, a rare stance among Angkor’s predominantly Hindu rulers, as seen in the numerous serene faces of the bodhisattva Lokesvara carved on the Bayon temple.

Signs of the empire’s decline became evident during the reign of his successor, Indravarman II (r. 1218–1243), during which Khmer control over Champa and some Thai territories was lost. Indravarman may have overseen a Hindu resurgence as the state religion, a trend intensified by Jayavarman VIII (r. 1243–1295), who systematically destroyed or altered many Buddhist images. Yet, from the 13th century, Theravada Buddhism began to take hold, likely influenced by the Mon and Thai peoples incorporated into the empire. This form of Buddhism found widespread acceptance, gradually eclipsing the traditional Hindu state religion. By the mid-14th century, Theravada Buddhism had become firmly established, shaping Cambodia into the predominantly Buddhist nation it remains today.