Scholars generally view twelfth-century anti-Jewish polemical writings of Petrus Alfonsi and Peter the Venerable as the first works of Christian polemic to cite extensively from the rabbinic aggadah (lore) of the Talmud, and historians frequently link the two’s familiarity with the Talmud to the emergence of rising anti-Jewish prejudice in the twelfth century. My project challenges the commonly accepted assumption that Alfonsi and Peter relied primarily on the Talmud as their source for the aggadah that they regularly cite and disparage. Drawing on surviving manuscript evidence, I argue that Alfonsi and Peter instead drew on a broader cultural ecosystem that included liturgy, homily, and legend, often bound together within the same codices. In addition to complicating our understanding of the shifting forms of anti-Jewish polemics, my research sheds light on the intertextual network of minor aggadic texts and homiletic literature from which these authors borrowed the passages they cited and the ways in which Jews and Christians approached these texts.