In the context of the capital cities of the Aragonese Kindom, it would be necessary to examineand compare the cerimonial practices, behavioral codes, and uses made of the royal residences. At the same time it seems increasingly evident that, during the 15th century, the mobility of the royal court - as well as that of the aristocrats, merchants, and master builders - slowly shaped a modern, homogeneous common language which is currently defined as "Mediterranean Gothic". This paper analyzes the contribution of Sicily through the study of a number of significant buildings : the royal palace of Palermo and the Steri of Chiaromonte , the castle Maniace of Syracuse .