10 Most Long-lived Empires in History

Khmer Empire

Little is known about the Khmer Empire, however, its capital city of Angkor was said to be awe-inspiring, thanks in part to the Angkor Wat, one of the world's largest religious monuments, built during the height of the Khmer's power. The Khmer Empire began in approximately 802 A.D. when Jayavarman II was declared king over the region now known as Cambodia. Six hundred and thirty years later, in 1432, it dissolved [source: Daniels].

The bulk of what we know about this empire comes from stone murals in the region, as well as firsthand accounts from Chinese diplomat, Zhou Daguan, who travelled to Angkor in 1296, and published a book on his experiences called "The Customs of Cambodia" [source: Diamond]. Most of its reign was marked by war as the Khmer attempted to grow ever larger and capture more territory. Angkor was the primary home of nobles in the latter half of the empire. Neighboring civilizations fought for control of Angkor when the Khmer's power began to wane.

Theories abound about why the Khmer Empire fell. Some believe that a king adopted Theravada Buddhism, leading to a loss of workers, degeneration of the water-management system and, ultimately, weak harvests [source: Leitsinger]. Others argue the Thai kingdom of Sukhothai conquered Angkor in the 1400s. Others believe the final straw came when the kingdom transferred power to the city of Oudong, leaving the city of Angkor all but abandoned.

In a broad sense, the Khmer Empire is another example of the danger of growing too large to sustain oneself. Click to the next page to see if this trend continues.