Around the mid-sixties, Francesco Celebrano was responsible for producing a floor with marble polychrome inlay, within which there was to be a continuous line of white marble without join, prodigious invention of the genius Raimondo di Sangro. The work – as the Prince states in his will – was “difficult and cumbersome”, so much so that it may not have been finished by the time of his death. However, what is certain of course is that the Floor Labyrinth covered the whole floor, as can be deduced from the many remains conserved in the Museum archives, as well as a nineteenth-century lithograph that shows – albeit in simplified form – the motif of the labyrinth.
The flooring Raimondo di Sangro wanted for his Chapel was thus very different from what we see now. A serious collapse, that involved the Palace and the Sansevero Chapel in 1889, damaged the original flooring so much that the restorers shied away from undertaking the complicated restoration; so the Chapel was re-floored in Neapolitan cotto, and enamelled in yellow and blue, the colours of the di Sangro arms.
Some slabs of the eighteenth-century flooring are visible today in the passageway in front of the Tomb of Raimondo di Sangro, and others are displayed in the Underground Chamber and the Sacristy. The design consists of alternate hooked crosses (swastikas), made up of a continuous line of white marble, with concentric squares in perspective. The polychrome inlay has different shades, from blue to white, giving depth to the composition. Along the perimeter of the nave there ran a darker band, it too decorated with an intricate line.
The choice of a labyrinth for flooring makes perfect sense in the allegorical language designed by the Prince for the Chapel. The labyrinth motif, belonging to ancient classical tradition rich in references to hermetic knowledge, represents the difficulty of the pathway which the initiate must follow if he is to gain knowledge. Dating back to the great astral myths of the Ancient World, it was widely held that the swastika symbolised cosmic movement; the concentric squares, alternating with the swastikas, are said to allude to the tetragon of the elements. Labyrinths, found in many gothic cathedrals and more generally in the so-called “abodes of philosophy”, are the alchemists’ image of the Great Work.