The so-called "Older Villach Workshop" was an important painting circle in Carinthia in the south of Austria, of the first half of the 15th Century, founded by the master Friedrich from Villach (Friderik Beljaski). Several wall paintings have been attributed to it by art historians; however some attributions were doubtful. The present research was carried out to obtain more information on the materials and painting techniques, which would allow us to distinguishbetween works that are genuine and those made by various followers. All works were studied in situ, and subsequently, small samples of plaster and pigments were extracted from selected areas. These were studied using different instrumental techniques: optical microscopy, SEM-EDS, FTIR and XRD. The results showed important similarities and also differences between wall paintings, observed in the composition of plaster, the use of incisions, pouncing, preparatory drawings, colour modelling, the choice of pigments and the combination of painting techniques (a fresco, a secco, lime technique). These differences confirmed that two of the selected wall painting cycles were painted by two different masters, who were, however, closely related to Friedrich.