The Early Middle Ages span roughly five centuries from 500 to 1000. During this period, most of Europe was Christianized, and the "Dark Ages" following the fall of Rome took place. The establishment of the Frankish Empire by the 9th century gave rise to the Carolingian Renaissance on the continent. Europe still remained a backwater compared to the rising Muslim world, with its vast network of caravan trade, or India with its Golden Period under the Gupta Empire and the Pratiharas or China, at this time the world's most populous empire under the Song Dynasty. By AD 1000, Constantinople had a population of about 300,000, but Rome had a mere 35,000 and Paris 20,000. Islam had over a dozen major cities stretching from Córdoba, Spain, at this time the world's largest city with 450,000 inhabitants, to central Asia.