Abstract
The Medici were one of the most powerful and influential families in European history. Through their success in commerce and banking, Florence became, from the 14th to the 18th century, the political and intellectual center in the Western world. The remains of family members were buried within the San Lorenzo Basilica in Florence. Before burial, the Medici nobles were subjected to an embalming process that included the removal of the viscera. The internal organs were placed in large terra cotta jars that were entombed along with the coffins of Medici nobles within the San Lorenzo architectural complex.
In this study we subjected viscera tissues from the embalming jars to microscopic and molecular analysis. Initial histological analysis using hematoxylin-eosin staining identified one of the tissues as a possible blood vessel that still contained traces of red blood cells. Further glycan analysis revealed sugars present on the blood cell surface that may indicate the B blood antigen. Unexpectedly, Giemsa staining provided the first indications for a parasite inside the red blood cells. This observation could not be supported by molecular analysis due to the absence of ancient endogenous DNA. However, when we extended our analysis to atomic force microscopy, we detected ring-like structures that resemble developmental stages of Plasmodium spp. or Babesia spp. parasites. Ultimately, immunohistochemistry confirmed the presence of Plasmodium falciparum inside the red blood cells and provided first microscopic evidence for the occurrence of the most fatal form of malaria in the Medici family.