Two Protestant books from the 16th century have been found in covers of two books which are kept at the Seminary Library in Ljubljana. The first one is an almost complete copy of the Croatian religious order »Crikveni ordinalicz« (1564), and the second one is a part of Trubar’s »Novi testament« (1582). The first book was most probably bound by Janž Mandelc, a printer from Ljubljana, and this is at the same time the first preserved proof, that he was occupied with book-binding also in Ljubljana. Both of these findings prove that Protestant books were also bound in Slovenia and not only in Germany, where they were mainly printed.