It should be pointed out at the start that St. Thomas had no unreasoned hatred of the Mohammedans. Rather, he prized their scholarship (although he disputed its conclusions), as the Mohammedan scholars in Moorish Spain, such as Averroes (whom St. Thomas called "The Commentator" [on Aristotle], as he called Aristotle "The Philosopher") had translated many Greek works into Latin. It is said that St. Thomas did not have an acquaintance with Greek in the thirteenth century, as such knowledge had been substantially lost in the West during the so-called Dark Ages, until the Fall of Constantinople in 1453, when the Greek scholars fled Constantinople for the West and were instrumental in starting the period known as the Renaissance, which prized its reacquaintance with the classical Greek authors.

St. Thomas's statement on Mohammed and his followers, found in his Summa Contra Gentiles, a more approachable treatise for many, who are challenged by the scholarly depth of his Summa Theologica. As a matter of fact, the Summa contra Gentiles was written to counter the philosophy of the Mohammedans, who had taken possession of large parts of Spain, who were not expelled until some 200 years latter, in 1492, by King Ferdinand and Queen Isabel. St. Thomas calls a spade and space and conforms to what we hear in the present day of things such as the seventy virgins awaiting Mohammedan murderers:

He [Mohammed] seduced the people by promises of carnal pleasure to which the concupiscence of the flesh urges us. His teaching also contained precepts that were in conformity with his promises, and he gave free rein to carnal pleasure. In all this, as is not unexpected, he was obeyed by carnal men. As for proofs of the truth of his doctrine, he brought forward only such as could be grasped by the natural ability of anyone with a very modest wisdom. Indeed, the truths that he taught he mingled with many fables and with doctrines of the greatest falsity.

He did not bring forth any signs produced in a supernatural way, which alone fittingly gives witness to Divine Inspiration, for a visible action that can be only Divine reveals an invisibly inspired teacher of Truth. On the contrary, Mohammed said that he was sent in the power of his arms -- which are signs not lacking even to robbers and tyrants. What is more, no wise men, men trained in things divine and human, believed in him from the beginning. Those who believed in him were brutal men and desert wanderers, utterly ignorant of all divine teaching, through whose numbers Mohammed forced others to become his followers by the violence of his arms.

Nor do divine pronouncements on the part of preceding prophets offer him any witness. On the contrary, he perverts almost all the testimony of the Old and the New Testaments by making them into a fabrication of his own, as can be seen by anyone who examines his law. It was, therefore, a shrewd decision on his part to forbid his followers to read the Old and New Testaments, lest these books convict him of falsity. It is thus clear that those who place faith in his words believe foolishly. (Lib. I, Chapter 16, Art. 4