Final answer:
Islamic cities declined after the Middle Ages due to fragmentation and infighting among Islamic empires, internal instability, and the rise of Western Europe.
Step-by-step explanation:
According to historical accounts, Islamic cities declined after the Middle Ages due to a variety of factors. One significant reason was the fragmentation and infighting among different Islamic empires, such as the Seljuks, Fatimids, and the rival caliphate in Spain. This internal instability weakened the political power of Islamic kingdoms and made them susceptible to attacks and colonization by Christian armies during the Crusades. Additionally, the decline of Islamic cities can also be attributed to the loss of political and military power in the face of the rise of Western Europe, which underwent radical changes in world politics, culture, and technology.