In this paper we present and discuss the origin and scientific significance of two works that are kept in the collection “Zaharija Orfelin’s Library” in the Patriarchate Library of the Serbian Orthodox Church in Belgrade. These are the first volume of “Veliki srpski travnik” (Eng. “Great Serbian Herbal”) and a newly discovered unidentified work of similar content. The aim of this study is to clarify the authorship of these works and bring them to the attention of the Serbian scientific community. In order to state the authorships precisely, all available literature on the subject has been reviewed. A comparison de visu of the copies of selected herbals from the Patriarchate Library in Belgrade, the British Library and the Royal Botanical Gardens at Kew in London, and at the Bavarian State Library in Munich has been conducted. For many years Zaharija Stefanović Orfelin (1726-1785), a Serbian versatile creator, has been credited with the authorship of “Veliki srpski travnik”, although it had been established as far back as in 1921 by Mita Kostić that its authorship is manifold. “Veliki srpski travnik” is clearly one of the copies of “Herbarium Blackwellianum”, created first as a “Curious Herbal” in 1735 by Elizabeth Blackwell (1707-1758), a British herbalist, and later redrawn by Nikolaus Friedrich Eisenberger (1707-1771), a German painter. Zaharija Orfelin bought a copy of the herbal and recreated it as a 3-volume work. For the first volume he assigned Serbian names for the plants to each of the 490 illustrated plates, and described the attributes and usage for 7 plants. Identification of a newly discovered work from the Patriarchate Library in Belgrade has not yet been confirmed for certain, as an ink analysis is needed to determine the time range of creation. However, the plates, the illustrations and the handwriting of Serbian plant names imply that most probably it is one of the two lost volumes of “Veliki srpski travnik”. Even if he is not the author of herbal’s concept and illustrations, Orfelin’s contribution in terms of botanical nomenclature was a significant milestone for the foundations of Serbian botany.