The 13th-century scholar Thomas Aquinas, regarded as one of the most eminent medieval philosophers and theologians, offered a biting critique of Islam based in large part on the questionable character and methods of its founder, Mohammed.
According to Aquinas, Islam appealed to ignorant, brutish, carnal men and spread not by the power of its arguments or divine grace but by the power of the sword.
Aquinas, a keen observer of the human condition, was familiar with the chief works of the Muslim philosophers of his day–including Avicenna, Algazel, and Averroes–and engaged them in his writings.
Since Islam was founded and spread in the seventh century, Aquinas—considered by Catholics as a saint and doctor of the Church—lived in a period closer to that of Mohammed than to our own day.
In one of his most significant works, the voluminous Summa contra gentiles, which Aquinas wrote between 1258 and 1264 AD, the scholar argued for the truth of Christianity against other belief systems, including Islam.