Petrus Alfonsi, an Andalusian Jew who converted to Christianity early in the twelfth century, was just one of the many scholars of his time who lived both in and between Jewish, Christian, and Islamic cultures and took upon themselves the task of acting as a bridge between these traditions. Alfonsi’s education in Arabic science, philosophy, and particularly astronomy–and his level of erudition was not particularly extraordinary given the standards in Islamic Spain–gave him something of great value to communicate to Christian Europe. He explains his project: “[I]t is proper that all those who have drunk of any philosophical nectar love each other, and that anyone who might have anything rare, precious, and useful which is unknown to others should impart it generously to others, so that in this way everyone’s knowledge may both grow and be extended in time” (Tolan 172–73). As a converso he sought to convince the Jews of their error in rejecting Jesus; as an Andalusian intellectual, he brought missionary zeal to the dissemination of Islamic and Jewish learning among the Christians of Europe.

Alfonsi lived in a period of great change. The latter half of the eleventh century heralded an enormous shift in the balance of power around the Mediterranean. Christian forces made significant advances both on the Iberian Peninsula, where the Islamic Taifa states were divided and weakened, and in Sicily, which in 1091 fell to the Normans. While these conquests diminished the political presence of Islam in Europe, perhaps paradoxically they also opened up Christian Europe to Arabic philosophical, scientific, medical, astronomical, and literary cultures. Not only had vast libraries like that of Toledo come into Christian hands, but the conquered population of Mozarabs, Andalusian Jews, and Mudejares produced a profound cultural impact: Mudejar architecture, thousands of Arabic loanwords, and new cultural forms such as the troubadour lyric – strongly suggestive of the Arabic and Hebrew strophic poetry (muwashshahs and zajals) born and popularized in al-Andalus.