Situated opposite the Santa Maria della Scala Hospital, it preserves an extraordinary artistic heritage that at times alludes to themes that intertwine with conceptions of humanist science. One of the most fascinating works is the inlaid flooring that was realised employing various techniques and in many stages between 1370 and 1550. They illustrate the story of man and the search for salvation. On entering the main door, worshippers are welcomed by the mythical figure of Hermes Trismegistus, symbolising the approach to the divine sphere by travelling the road of wisdom. What this represents is the beginning of earthly knowledge which, at the same time, introduces one to sanctity, represented by the temple. Hermes Trismegistus wears a white robe (symbol of the Revelation) and stands out against a black ground (symbol of non-knowledge). The chromatic solutions adopted are particularly fascinating as they refer to the alchemic symbology of colours. The alchemists indeed proposed a quite distinct chromatic scale: they attributed black to matter, the occult, sin; grey to the earth; white to mercury, innocence, illumination; red to sulphur, blood, passion, sublimation; azure to the sky; gold to consummation (the divine Great Opus).

Also noteworthy is the granite central column of the pulpit by Nicola Pisano that rests on a sculptural group with depictions of the Liberal Arts: Grammar, Dialectics, Rhetoric, Philosophy, Arithmetic, Geometry, Music and Astronomy.