In 1423, Shimʿon b. Ṣemaḥ Duran, who had fled his native Majorca after the anti-Jewish riots 1391 and settled in Algiers, wrote an anti-Islamic polemic titled Bow and Shield (Qeshet u-magen). Unlike his Jewish predecessors arguing against Islam, Duran did not defend the Hebrew Bible and Rabbinic tradition, but attacked the rationality of Islam by scrutinizing the Qurʾānic teachings concerning God's existence, theodicy, punishment or reward in the afterlife, and the Islamic concept of the inimitable linguistic perfection of the Qurʾān.
Duran's labelling of Islam as an irrational and materialistic religion and his depiction of the Qurʾān as a composition rife with confusion is a well-known topos of Christian anti-Islamic literature such as Ps. al-Kindi, Roger Bacon or Ramon Marti. This paper will discuss the motifs Duran appropriated from Christian anti-Islamic polemic in Bow and Shield as well as their possible sources. It will show that Duran's polemical method is rooted in the specific cultural milieu of medieval Spain, where all three traditions-Judaism, Christianity, and Islam-intermingle and become entangled in the polemical genre.