In the Underground Chamber, housed in two glass cases, are the famous Anatomical Machines, i.e. the skeletons of a man and of a woman in upright position, with the artery and vein systems almost perfectly intact. The Machines were made by the doctor Giuseppe Salerno of Palermo, under the direction of Raimondo di Sangro. The discovery of notaries’ deeds and credit notes makes it possible to date these “works” to 1763-64. The two anatomical studies are the most enigmatic objects in the Sansevero Chapel. Still today, after about two-and-a-half centuries, it is still not known which procedures or materials were used to obtain such an exceptional preservation of the circulatory system.
The Short note, an anonymous eighteenth-century guide to the Palace and the Sansevero Chapel, speaks of “injection”. It was proposed that Salerno injected a substance – perhaps based on mercury – into the two corpses. The substance would have been created in a laboratory by the Prince of Sansevero, and would allow the “metallisation” of the blood vessels. The other possibility is that the circulatory system is the fruit, in part or wholly, of reconstruction carried out using different materials, among which are beeswax and some colorant. This second case would not deprive the two Machines of their exceptional nature. It is, in fact, amazing that the arteries and veins are reproduced with remarkable realism, even the smallest vessels, despite the fact that knowledge of anatomy was not so precise. The bones and skulls are without doubt those of two real human skeletons.
These disquieting objects were kept in a room in the palace of the Prince of Sansevero, called “the Apartment of the Phoenix”, as a number of travellers and the Short note attest. This source describes the Machines in detail, from the blood vessels of the head to those of the tongue, and adds that at the feet of the women was placed “the tiny body of a foetus”, alongside which there was even the open placenta, connected to the foetus by umbilical cord. The two anatomical studies were moved to the Chapel, and in this way saved from destruction or loss, long after the death of the Prince. The remains of the foetus were still visible up to a few decades ago, until they were stolen.
The Anatomical Machines have fuelled the so-called “black legend” about the Prince of Sansevero. Also Benedetto Croce recounts that, according to popular belief, Raimondo di Sangro “had two of his servants killed, a man and a women, and had the bodies strangely embalmed so that they showed all the viscera, the arteries and the veins”. These experiments need to be contextualised within the wide-ranging spectrum of experiments and interests of the Prince of Sansevero, who also took an interest in medicine. Furthermore, the skeleton of the woman was on a base and could be made to “turn right round so as to allow observation of all the parts”, which leads to the conclusion that Raimondo di Sangro had designed it as an object of study. It should not be forgotten, however, that he intended to – and succeeded in – amazing contemporary and future observers, and the original location of the Machines in the Apartment of the Phoenix is significant, given the association of the bird in question with the myth of resurrection and immortality.