Elementary geometry in staircases design. The ‘city house’ of Bernardo Antonio Vittone

This study is part of a research on the geometric matrices analysis of eighteenth-century residential staircases in Naples (Italy). The research was conducted through the architectural survey of various examples, then cataloged through the planimetric schemes geometric analysis. From this comparison, the staircases examined are attributable to elementary geometric shapes, from which complex solutions derive. In the eighteenth-century, the Neapolitan architect who lends a scenic role to the noble residences’ staircases, thanks to the creative use of elementary geometric shapes, was Ferdinando Sanfelice (1675–1748). Among the many possible geometric configurations, the 45° rotation of two squares of equal size and their overlapping parts generates an irregular hexagon. This solution is the figurative matrix of the Palazzo Cassano Ayerbo d’Aragona staircase. We can find the same architectural experimentation in the treatise on civil architecture by Bernardo Antonio Vittone (1704–1770). In “Volume One” of the Treaty, Istruzioni diverse concernenti l’officio dell’architetto civile, Vittone publishes the project of a “City House” where the staircase design presents a shape surprisingly similar to that of Palazzo Cassano Ayerbo d’Aragona. Recent studies suggested that the Palazzo Cassano Ayerbo d’Aragona staircase design could be attributed to Ferdinando Sanfelice. In the absence of documentary sources, we wonder about the possible relations between Sanfelice and Vittone and/or a possible treaty writer visit to the Palazzo Cassano Ayerbo d’Aragona where Vittone, surprised by spatial complexity of the staircase, would have taken cue to replicate its geometric matrix in the project of the “City House”.