13. CREATING A NEW LITERARY GENRE: STEINSCHNEIDERS LEIDEN CATALOGUE Steven Harvey and Resianne Fontaine Introduction Moritz Steinschneider published his Catalogus Codicum Hebraeorum Bibliothecae Academiae Lugduno-Batavae in Leiden in 1858. As we shall show, this pioneering and quite extraordinary catalogue of Hebrew manuscripts had a signicant impact on those who sought to unders- tand and tell the story of the development of medieval Jewish thou- ght. In particular, this works unusually detailed description of manuscripts and lengthy quotations from them, along with select bibliographic information on the texts contained in the manuscripts, soon turned it into a much-needed tool for the study of knowledge transfer from the world of Islam to the world of Judaism. The pre- sent paper focuses on its importance for the study of medieval Jewish philosophy. After briey surveying the pre-Leiden catalogues and listings, we will recount the purpose and format of the Leiden catalogue. We will then explore the importance of the Hebrew philosophic manuscripts it describes, and to what extent Steinschneider was aware of their impor- tance and made it known to his readers. We will also describe how the Leiden catalogue differs from previous ones in presenting its works on Jewish philosophy. We will then compare the Leiden catalogue to later catalogues by Steinschneider and others to determine to what extent the later catalogues follow the purpose and structure of the Leiden one. After these comparisons, we will trace the use made of the cata- logue by historians and bibliographers of medieval Jewish philos- ophy, in particular Ernest Renan (18231892) in his revised and expanded edition of Averroès et laverroïsme: essai historique (Paris, 1861). Finally, we will suggest in what sense it may be said to represent a new literary genre.