Like the other works in the Chapel, Sincerity too was designed by Corradini, who had made a scale model, but the group shows the wholly personal touch of Queirolo who, as Giangiuseppe Origlia says, “laboured” on this marble in 1754. Virtue is dedicated to the wife of Raimondo di Sangro, Carlotta Gaetani. As the monument was erected while Carlotta was still alive, here too – as in the case of the Sweetness of the Marital Yoke – the portrait engraved in the medallion is not fully outlined.

A woman of serene beauty, wrapped in static drapery gathered with grace and elegance, holds a heart in her left hand, and in the right a caduceus, the former being a symbol of love and charity, and the other of peace and reason. Below, we can admire a chubby putto of admirable workmanship – perhaps by Paolo Persico – and two doves representing purity, marital loyalty, fertility and, in the language of alchemy, the albedo of raw material, before its transformation into the philosopher’s stone. The plaque on the column, exalting the qualities of the noblewoman, was made by Raimondo di Sangro in 1758.

The model of Sincerity – like the other Virtues – follows the canons established by the Iconologia of Cesare Ripa (first edition: Rome 1593), but there are some evident variations, the most important of which is the caduceus. It is made up of a rod around which two serpents are entwined. This was the pagan symbol of Hermes/Mercury, and later represented the Hermetic science. In alchemy, the caduceus symbolises the coincidentia oppositorum, or the union of opposites, sulphur and mercury. Like three other marble groups, Sincerity too is characterised by one side of a pyramid against a column.

This work by Queirolo is a perfect example of the original interpretation that the Prince’s idea gives to the iconographic principles established by tradition. The exaltation of the virtues of Carlotta Gaetani is enriched, thanks to the addition of new symbols, with other meanings and other allusions.