In the thirteenth century Raymundus Martini – or in Catalan: Ramon Martí – wrote his huge polemical treatise Pugio fidei (‘Dagger of Faith”) directed against all enemies of Christianity, in particular against Muslims and Jews. Some years ago a manuscript kept in a Parisian library was identified as the Dominican friar’s autograph, which contains many more texts than the seventeenth-century print editions. Also the texts employed are sometimes different from the printed editions. Most striking is the continuous vocalization of the Hebrew. This article introduces Martí’s use of the Jerusalem Talmud. The fact that he could use that text is in itself remarkable because it means that at least one manuscript was circulated in medieval Catalonia. The texts which Ramon Martí had collected are presented in a newly-established transcription from the autograph.