Middle East over the last 1,200 years. 1.1 indicates that in 800, the urban share of the population of the Islamic world was much than in Christian Europe. 4 Fourteen of the twenty-two largest cities in Europe and the Middle East, including by far the largest city-the Abbasid capital Baghdad-were under Islamic rule. The Umayyad (Cordoba) Caliphate in modern-day Spain and the Abbasid Caliphate, centered in modernday Iraq, ruled the most populous and wealthiest areas. Seven of the eight most populous cities were Muslim-ruled, with only the Byzantine capital Constantinople containing a large urban population of Christians. In fact, the combined population of the top thirteen cities of Christian Western and Central Europe