Renaissance mercurial therapy in the mummies of Saint Domenico Maggiore in Naples: a palaeopathological and palaeotoxicological approach

This study was designed to evaluate the use of mercury therapy in the Italian noble classes of the Renaissance through the toxicological analysis of hair content. Mercury has stability and a long half-life in hair, representing a great resource not only for forensic toxicological analysis but also for archaeological research on mercurial exposure in past populations. The hair of fourteen mummified individuals of the Aragon and vice-royal court of Naples, buried in the Neapolitan Basilica of Saint Domenico Maggiore (15–18th centuries), was analysed by atomic absorption spectroscopy (AAS) and flame emission spectroscopy (FES). Out of the fourteen individuals, four presented mercury concentrations in the hair washing liquid indicating external perimortem application (in one case clearly linked to embalming, in three cases probably associated with topical therapeutic practices), three showed no traces of mercury, and seven had mercury values in hair ranging from 411 to 47 ppm, which indicate prolonged exposure in life to the metal. The historical identification of most of the mummified bodies with important nobles of Naples has allowed to compare the toxicological analyses with the nosography of the individuals and with the palaeopathological results deriving from the direct study of their bodies. Prolonged exposure in life to the metal was most likely due to mercurial anti-syphilitic therapy, as a consequence of its indiscriminate use in Renaissance therapies and, indirectly, as an effect of the extraordinary spread of venereal syphilis in the Italian upper classes during the “epidemic” phase of the disease.