Alexander Kronemer has written an article on Islamic Spain that points out that Spanish society was more religiously tolerant and pluralistic under Islam than much of Christian Europe was at that time. Here are some of his comments:
Islamic Spain lasted longer than the Roman Empire. It marked a period and a place where for hundreds of years a relative religious tolerance prevailed in medieval Europe.
At its peak, it lit the Dark Ages with science and philosophy, poetry, art, and architecture. It was the period remembered as a golden age for European Jews. Breakthroughs in medicine, the introduction of the number zero, the lost philosophy of Aristotle, even the prototype for the guitar all came to Europe through Islamic Spain.
Not until the Renaissance was so much culture produced in the West. And not until relatively recent times has there been the level of pluralism and religious tolerance that existed in Islamic Spain at its peak. Just as the vibrancy and creativity of America is rooted in the acceptance of diversity, so was it then.
Because Islam's prophet Muhammad founded his mission as a continuation of the Abrahamic tradition, Islamic theology gave special consideration to Jews and Christians. To be sure, there were limits to these accommodations, such as special taxes levied on religious minorities. But in the early Middle Ages, official tolerance of one religion by another was an amazingly liberal point of view. This acceptance became the basis for Islamic Spain's genius. Indeed, it was an important reason Islam took hold there in the first place.
When the first Muslims crossed the straits of Gibraltar into Spain, the large Jewish population there was enduring a period of oppression by the Roman Catholic Visigoths. The Jewish minorities rallied to aid the Arab Muslims as liberators, and the divided Visigoths fell.
The conquering Arab Muslims remained a minority for many years, but they were able to govern their Catholic and Jewish citizens by a policy of inclusiveness. Even as Islam slowly grew over the centuries to be the majority religion in Spain, this spirit was largely, if not always perfectly, maintained.