Why in the X century the urban economy on the Iberian Peninsula was developed as highly as in the Balkan

Why in the X century the urban economy on the Iberian Peninsula was developed as highly as in the Balkan, but much higher than in other states of Western Europe?

In the 10th century, Arab Spain retained an urban culture brought in from the Middle East; here, as in the Balkans, the barbarians were “cultivated” by a more civilized people, and did not subjugate them, as happened, for example, in Gaul and on the Danube.