The period of the Caliphate is seen as the golden age of al-Andalus. Crops produced using irrigation, along with food imported from the Middle East, provided the area around Córdoba and some other Andalusī cities with an agricultural economic sector that was the most advanced in Europe by far, sparking the Arab Agricultural Revolution. Among European cities, Córdoba under the Caliphate, with a population of perhaps 500,000, eventually overtook Constantinople as the largest and most prosperous city in Europe.Chandler, Tertius. Four Thousand Years of Urban Growth: An Historical Census (1987), St. David's University Press (etext.org ). . Within the Islamic world, Córdoba was one of the leading cultural centres. The work of its most important philosophers and scientists (notably Abulcasis and Averroes) had a major influence on the intellectual life of medieval Europe.
