Historians have always assumed that the medieval city of Angkor, today located in Cambodia, was huge, simply based on how much land its kings commanded. From the ninth to the 15th centuries, Angkor was the capital of the Khmer empire, which at its zenith stretched across modern Cambodia, Laos, Thailand, and Vietnam. The city was thronged with visitors from all over Southeast Asia—royalty and peasants alike—and was home to large numbers of farmers who kept the city fed, as well as workers who built its palaces, canals, and reservoirs. But precisely how many people lived in Angkor is one of the enduring mysteries in archaeology.
The problem is that, centuries after the city’s decline, only the great walled temples at Angkor Wat and Angkor Thom remain standing. The city’s residential neighborhoods were made entirely of perishable materials such as wood. Angkor’s city grid quickly disappeared beneath thick vegetation, and farmers ploughed over its far-flung neighborhoods. Though generations of experts have studied the city’s ruins, they’ve been unable to come up with a reliable estimate of its population that would help them make sense of how such a large city was run.
Now the Leiden University archaeology researcher Sarah Klassen and her colleagues believe that they’ve found the magic number. Based on a comprehensive analysis using nearly 150 years of data, they peg the peak population of the greater Angkor region at 700,000 to 900,000 people in the 13th century. The only European city approaching that size at the time was Constantinople.