The present paper focus on an interdisciplinary research of Cultural Heritage concerning the microanalysis of Gothic mural paintings made during the 15th century in Slovenia. The samples were chosen from the churches of Crngrob (1453), Mirna (1463-65), MevkuG (1465) and MaHe (1467), attributed to two of the most important Gothic painters of that period of time: Master Bolfgang and Master of MaHe. The chemical and phase composition of all the mortars was of interest, the number of their layers and the selection of the pigments. For this purpose, fragments of mural paintings were studied with several instrumental techniques: OM, SEM-EDX, XRD and FTIR. In early artworks, the mortar was made using a mixture of lime and more or less clean sand. Later, crushed lime-rock or marble instead of sand was added to lime. The pigments identified by EDX microanalysis of cross-sections previously studied by OM, are of earth or mineral origen. Therefore, they are durable in fresco and lime technique: lime white, yellow and red natural or burned ochres, green earth and azurite. The results confirmed the high technical quality of both painters and the relationships between the teacher and the disciple. Master Bolfgang and Master of MaHe combine three basic techniques of mural painting: a fresco, a secco and lime technique. This kind of investigation and methodology allow us to know better the Central European Art and the Slovenian Art in the Adriatic zone, as well as the general map of European Art in the 14-15 centuries.Peer reviewed