From The Schiller Institute:
In Dante’s Commedia, the poetical masterpiece which ushered in the Golden Renaissance, Mohammed, the prophet of Islam, is consigned to the ninth circle of Inferno. He is condemned by the Christian poet, not because he is considered a heretic, but because the religious movement he inaugurated was considered schismatic. Dante placed the Muslim philosopher and scientist Ibn Sina in Limbo, in the august company of Plato and Socrates, and Salah al-Din, the Muslim leader who recaptured Jerusalem in 1187. One of the most famous paintings of the early Renaissance (c. 1340), by Francesco Traini, depicts Saint Thomas Aquinas stomping a figure under his feet, as if it were a snake depicting Satan. The figure under his feet is the Twelfth-century Andalusian philosopher Ibn Rushd, known more commonly as Averroes, who was largely responsible for reintroducing Aristotle into Europe. Was Aquinas, then, a crusader against the infidel Saracen? Or Cardinal Nicholas of Cusa, whose ecumenical efforts at the 1439 Council of Florence forged the union of Christendom on the basis of an image of man which was to spark the Renaissance? Cusa, whose Cribatio Alcoranus was a theological critique of Islam, was yet the same man who defined the parameters for an ecumenical understanding among all faiths, including Islam, in his De Pace Fidei.
Islam, for medieval Christian Europe, was not an abstract religious faith. It was the lifeblood of a vibrant culture which flourished on European soil, in Al-Andalus, from the coming of the Arabs to Spain in 711 until their expulsion under Ferdinand and Isabella in 1492. Andalusia, particularly from the Ninth to the Thirteenth centuries, was a beacon of learning, in a Europe languishing, for the most part, in the shadows of ignorance and economic-social backwardness. Islamic culture had flourished as well in the teeming metropolises of Baghdad, Damascus, Samarkand, Bukhara, and Cairo, but it was Moorish Spain which most affected Europe.
More here. (Note: Although old in terms of publication date, this article is worth reading for those interested in a history of monotheistic relegions.)