The paper deals with three medieval scholars, their life and works, which can be considered as encyclopaedias. In the funds of Slovak National Library are stored the prints of their works, which belong to the incunabula period. The first of the scholars is Isidore of Seville and his most famous work Etymologiae, which was studied throughout the Middle Ages. The print of this work from the year 1473 offers interesting decorations, such as woodcut illustrations displays seasons of the year or a description of the winds. The manuscript marginalia in this print are found in chapters such as church history, Christian faith, or descriptions of minerals and rocks. The second author is Bartholomaeus Anglicus and his work De proprietatibus rerum, also very popular in the 15th century. It contains many manuscript marginalia on a religious and economic theme, especially from the 17th century. The former owner of this print was, among others, Franciscan monastery in Nižná Šebastová. There are also unusual handwritten marginalia such as pointing hands. The last watched author is Vincent of Beauvais and the work Speculum maius specifically its part Speculum doctrinale. This print is important for its decoration. It contains initials decorated with red and blue ink and various displays of characters. The owners were Premonstratensian monastery in Jasov and Dominican monastery from the Italian city of Bolzano. Bindings and watermarks are described in each presented work. Encyclopaedic works from the incunabula period, offer not only interesting content from the point of view of cultural and educational research, but also possibilities for a more detailed description of the prints themselves.