** The connection between City Size and Leading Civilizations In the past, the largest cities of the world were often part of the leading civilization of the time, typically the capital city This extends from Memphis, Egypt in 3000BC to New York City from 1925 to 1965. Up to 1300, there were only brief exceptions: Ctesiphon, Iraq 570, Merv (Mary), Turkmenistan 1145, and Fez (Fes), Morocco 1170. Some large cities, like Patna in India, did not achieve leading civilization status until much later. And some, like Rome, became leading civilizations before their capitol's population became the world's largest. The European Renaissance de-linked city size with being the leading civilization. The fact that Cairo of 1300 was a huge city did not make Egypt a leading civilization. But that did help its trading partner and sea power, Venice, become rich. For the next several centuries, Middle East and Asian cities grew large, while European nations became leading civilizations in the sciences and arts. Largest cities (with year and population) were: Nanking, China 1358 487,000 (1400); Beijing, China 1425 600,000 (1450); 672,000 (1500); Constantinople (Istanbul), Turkey 1650 700,000 (1650 & 1700); and again Beijing, China 1710 900,000 (1750). It wasn't until 1830 that a European city, London, became the world's most populous as well as most advanced. That was followed by technologically advanced New York and Tokyo. In the latter part of the 20th century, the world's largest cities have again become unrelated to leading civilizations, in places like Mexico City and Sao Paulo, Brazil.

See http://geography.about.com/library/weekly/aa011201a.htm for a list of the world's largest cities through time.