In the present paper, the typical complexities of masonry structures are investigated and discussed throughout the case of San Carlo all'Arena Convent in order to underline their structural implications. It is a masonry building located in Naples that has a strong historical interest because of its different occupancy over time. It is part of an aggregate; in particular it has adjacent structures, as buildings with different height and a church. Located on a hill, the Convent case study is characterized by variable height and a rectangular plan with a courtyard. During its history, it was subjected to modifications, as the additions of parts in plan and of floors, and alterations, as openings which are often misaligned in vertical direction and are not characterized by the same sizes as the existing ones.

For this reason, this masonry building allows the analysis of the typical complexities of masonry structures, as the issues of aggregates, addition of floors, the presence of different occupancy, foundations at different heights and the presence of alterations, as addition of openings.