Church of Nostra Signora de Sos Regnos Altos in Bosa is one of the few Sardinian examples of a Palatine Chapel within a citadel, situated in the complex of the castle Serravale on the northwest coast of the island. The importance of this monument is determined primarily by painting cycle of the church interior, which stretches to the north, south and entrance wall. Since these paintings are unique in the island’s art corpus, the researchers sought to identify their patrons and masters, the main models and the iconographic and stylistic references. R. Sfogliano dates the cycle to 15th century, F. Bologna and P. Leone De Castris connect it to the work of Maestro di Offida, R. Serra and R. Coroneo propose the second half of the 14th century, with a range of different influences while A. Caleca assumes that a painter, active in Bosa, could have brought the Pisan and Sienese influence in the first year of 14th century. The monograph of the frescoes in Bosa by F. Poly, published in 1999, brings a historical frame and analysis of the frescoes proposing the dating and a reference framework which is still considered relevant. The most famous scene of the cycle is, no doubt, Encounter of the three living and the three dead. The presence of this theme seems closely connected with the guiding principle of the fresco decoration: memento of inevitable death united with call for reflection on the vanity of earthly existence. Painting cycle in Bosa represents different degrees of complexity. Lack of documents and accurate information lead to hypotheses such are claims by F. Poly, who has recognized in it the cycle hand of a Tuscan painter as well as a comissioner, Arbore Giovanni, brother of the future ruler of the Kingdom of Arborea, Mariano IV, resident of Seravalle castle between 1338 and 1345. However, the value of frescoes in the church of Nostra Signora de Sos Regnos Altos, which are the key part for the reconstruction of historical and artistic mosaic of Sardinia in the 14th century, is indisputable.