Baghdad was likely the largest city in the world from shortly after its foundation in 762 AD until the 930s, with some estimates putting its population at over one million.[34] Chinese capital cities Chang'an and Kaifeng also experienced huge population booms during prosperous empires. According to the census in the year 742 recorded in the New Book of Tang, 362,921 families with 1,960,188 persons were counted in Jingzhao Fu (京兆府), the metropolitan area including small cities in the vicinity of Chang'an.[35] The medieval settlement surrounding Angkor, the one-time capital of the Khmer Empire which flourished between the 9th and 15th centuries, could have supported a population of up to one million people.[36]