The purpose of the work is to investigate the recording of data on the former ownership of books in library catalogues. The paper will define provenance and explain the purpose of recording provenance data in library catalogues. The importance of the CERL thesaurus and the importance of digitizing the old and rare books will also be highlighted. The aim of this study is to investigate whether the data of provenance presented in catalogues that list the collections of books of famous Croatian families Martinis-Marchi and Pejačević and the books of Regional museum of Rovinj and Museum of Split, are included in CERL thesaurus. The research will identify the main problems with the recording of provenance and propose improvements. The research was conducted by examining the catalogues of the Pejačević and Martinis-Marchi families and the catalogues of Regional museum of Rovinj and Museum of Split by searching the CERL thesaurus and comparing the data. In addition, the project Digitized heritage of the National and University Library in Zagreb was presented and also the Zriniana collection of Zrinian family, which is part of that project.