Geometry and Perspective Illusionism in Italian Renaissance: Altar of Annunciazione in Naples by Benedetto da Majano

The aim of this work is to detect the existence of a true perspective method used by the Renaissance artist Benedetto da Majano in the Annunciazione, a Neapolitan marble relief built at the end of the fifteenth century. The study consists of a metric and photogrammetric analysis of the relief, comparing its own perspective configuration with the actual knowledge of Solid Perspective, based on Descriptive and Projective Geometry. Thus, a precise correspondence has been found between sculptural space and geometric laws, even in the small decorative details, despite the objective difficulty to engrave the friable marble mass. The illusion is here attained by means of three different perspective levels - the first two realized in high-relief and the third, as a backdrop, in bas-relief - that progressively lead the observer to dynamically approach the virtual image of the space; all this happens in a marble depth of only twenty centimetres! We cannot say exactly what was the executive method utilized by the artist to pass from the real to the perspective space, whether he used ropes as visual rays, or gradually imprinted a picture in the marble, or used other processes. However, the rigour of perspective construction also acquires symbolic meanings.