This study seeks to analyze and historicize the document entitled Süleymaniye Kütüphanesi Defteri (Süleymaniye Library Inventory), which is present in the Pious Endowments Archive in Ankara under call number 2011. The inventory, which has not received attention in the field of library studies so far, consists of three sections. The first section lacks its first page and can only be identified by the presence of the phrase “mühr-i sultânî” (sultanic seal). The second and third sections list the books that Mehmed Şâh and Mollâ Ahaveyn endowed, respectively. It is believed that the book inventory represents the books endowed by Süleyman I to the Süleymaniye Medreses and that it was compiled and re-listed during the reign of Murad III. In this context, the inventory provides valuable information about the quantity and quality of the books that existed in the mosque before Mahmud I reorganized the collections in the Süleymaniye Mosque and established a library there called the Süleymaniye Library in 1752.
