The Royal Library has rich collections of Judaica (materials on Jewish Studies in Western languages) and Hebraica (material written in Hebrew scripts). Already in the Renaissance, the Jewish roots of Christianity led to the acquisition of manuscripts, and later, printed works, for the royal collections. In the 17th century, and particularly in the 18th century, the collections were expanded by acquisitions in Denmark, but also abroad, as Danish explorers bought manuscripts and printed works. In the 19th century, the growing discipline of Jewish Studies and the emergence of Biblical criticism led to further expansion of the collections. A pivotal moment came in 1932, with the acquistion of professor, Rabbi David Simonsen's private library and archives.
Materials in Hebrew, Aramaic, Yiddish, Ladino etc., are all included in the Judaica Collection, whereas materials in Western languages in general belong to other collections in the National Library and Copenhagen University Library. Regardless of language, all printed and digital materials (with the excption of the Hebrew incunables) should be searched for and ordered in the online catalogue REX, for use in reading rooms or for lending. Manuscripts and early printed works can only be examined by agreement.