Petrus Alfonsi's Dialogue Against the Jews (ca. 1109) breaks new ground in the history of Christian anti-Jewish polemics. As a recent convert from Judaism, Alfonsi introduced an intimate knowledge of Jewish literature and contemporary practice absent from earlier Christian sources. This knowledge enabled him to attack for the first time the Talmud (or, more broadly, post-biblical Jewish literature) as a source of Jewish error, with arguments drawn from philosophy and theology, astronomy, medicine, and physics. Equally important, Alfonsi's Dialogue contains an extensive anti-Muslim polemic to explain not only why he abandoned Judaism but also why he rejected Islam and chose the Christian faith. For these reasons the Dialogue has been described as the most important anti-Jewish text of the Latin Middle Ages. This assessment is based not only on its innovative argumentation but also on the fact that it was one of the most popular medieval anti-Jewish polemics written. It was cited, often verbatim, by later Christian polemicists like Peter of Blois and used by Peter the Venerable. Alfonsi's Dialogue was known to Joachim of Fiore, who adapted its illustration of the mystery of the Trinity contained in the tetragrammaton; summarized by Vincent of Beauvais, who included a long extract from the Dialogue in his popular Speculum historiale ; exploited by Raymund Martini in his monumental Pugio Fidei ; and utilized by Abner de Burgos in his Mostrador de Justicia . It was also likely employed by Pablo Christiani to prepare for the public disputation at Barcelona (1263 C.E.) and later by Jerome de Santa Fe for the disputation at Tortosa (1413-1414 C.E.). Never before translated into English, this work presents to the reader perhaps the most important source for an intensifying medieval Christian-Jewish debate.
Petrus Alfonsi (born Moses Sephardi) (c.1062 - 1110) was a Jewish Spanish physician, writer, astronomer, and polemicist, who converted to Christianity in 1106. He is also known just as Alphonsi, and as Pedro Alfonso, Peter Alfonsi or Peter Alphonse. Born in Islamic Spain, he mostly lived in England and France after his conversion.
He was born at an unknown date and place in the 11th century in Spain, and educated in al-Andalus, or Islamic Spain. As he describes himself, he was baptised at Huesca, capital of the Kingdom of Aragon, on St. Peter's Day, 29 June 1106, when he was probably approaching middle age; this is the first clear date we have in his biography. In honor of the saint Peter, and of his royal patron and godfather, the Aragonese King Alfonso I he took the name of Petrus Alfonsi (Alfonso's Peter).
By 1116 at the latest he had emigrated to England, where he seems to have remained some years, before moving to northern France. The date of his death is as unclear as that of his birth. He was famous as a writer during his lifetime, and remained so for the rest of the Middle Ages, with over 160 surviving medieval manuscripts containing works of his. The most common are his Dialogi contra Iudaeos (Dialogue Against the Jews), an imaginary conversation between a Jew and a Christian, and Disciplina Clericalis (A Training-school for the Clergy), in fact a collection of Eastern fables.
Been reading this for my thesis and probably read through it twice now (once in Jan. 2021). Not gonna really count books I'm reading for my course unless I really properly read it cover to cover (i.e. not counting books where I just read a chapter or something)