The diploma thesis deals with medieval mural paintings. Its aim is to describe and classify the collection in terms of time and style in the context of contemporary production of mural paintings in the 14th century in Bohemia. In the introduction, historical realtionships connected with the Cathedral of the Holy Spirit are described and the development of church service in East Bohemia is outlined. The main part is concerned with the description, placement, iconographical determination of mural paintings and their present state. It especially focuses on analysing and specification of the iconography of different scenes, figures of saints and donators. Style analysis qualifies style resemblance, analogy, parallels and confronts the mural paintings with contemporary book, mural and carving production. It also deals with the problematics of over painting accidental intervention into the monument. This part deduces the probable creation time of the whole interior decoration of the decanal sacristy. The final part evaluates and recapitulates the whole problematics. The diploma thesis offers the first detailed analysis and evaluation of the paintings in the decanal sacristy of the Cathedral of the Holy Spirit in Hradec Králové and provides complete drawing and photographic documentation.