Shortly after the cardinal’s arrival, Francesco and Bianca fell ill with ominous symptoms: convulsions, fever, nausea, severe thirst, gastric burning. Within days they were dead. Cardinal Ferdinando buried his brother with great pomp (Bianca was interred separately) and banished his nephew Antonio to a golden exile—whereupon Ferdinando crowned himself the new Grand Duke of Tuscany.
Rumors spread swiftly that the couple had been murdered. Cardinal Ferdinando, some whispered, had cleared his path to the ducal throne by killing the couple with arsenic, often preferred by Renaissance poisoners because it left no obvious traces on its victims. Others said that Bianca herself had baked an arsenic-laced cake for her detested brother-in-law, which her husband had tasted first by mistake; overcome with horror, Bianca supposedly ate a slice of the deadly confection as well, in order to join her beloved Francesco in the grave. A cloud of foul play enshrouded the unfortunate pair for centuries.
In 2006, four medical and forensic researchers from the University of Florence and the University of Pavia, led by toxicologist Francesco Mari, published an article in which they argued that Francesco and Bianca had died of arsenic poisoning. In the British Medical Journal, they described collecting tissue samples from urns buried beneath the floor of a church in Tuscany. At that church, according to an account from 1587 recently uncovered in an Italian archive, the internal organs of Francesco and Bianca, removed from their bodies, had been placed in terra-cotta receptacles and interred. The practice was not uncommon. (Francesco is buried in the Medici Chapels in Florence; Bianca’s grave has never been found.) Mari contended that the tissue samples—in which concentrations of arsenic he deemed lethal were detected—belonged to the grand duke and duchess. The rumors, argued the researchers, had been correct: Cardinal Ferdinando had done away with Francesco and his bride.
Fornaciari dismantled this thesis in two articles, one in the American Journal of Medicine, both of which showcased his wide-ranging skills as a Renaissance detective. Tissue samples recovered from the urns were likely not from the doomed Medici couple at all, he wrote. Those samples, he added, could have belonged to any of hundreds of people interred in the church over the centuries; in fact, the style of two crucifixes found with the urns attributed to Francesco and Bianca dates from more than a century after their deaths.
Even had the tissues come from the couple—which Fornaciari strongly doubts—he argued that the levels of arsenic detected by Mari were no proof of murder. Because arsenic preserves human tissue, it was routinely used in the Renaissance to embalm corpses. Since the couple’s bodies had certainly been embalmed, it would have been surprising not to have discovered arsenic in their remains. Fornaciari added that since Francesco was a passionate alchemist, arsenic in his tissues could well have come from the tireless experiments he performed in the laboratory of his palace in Florence, the Palazzo Pitti.
As a coup de grâce, Fornaciari analyzed bone samples from Francesco, showing that at the time of death he had been acutely infested with plasmodium falciparium, the parasitic protozoan that causes pernicious malaria. Fornaciari observed that malaria had been widespread in the coastal lowlands of Tuscany until the 20th century. In the three days before they fell ill, Francesco and Bianca had been hunting near Poggio a Caiano, then filled with marshes and rice paddies: a classic environment for malarial mosquitoes. He pointed out that the symptoms of Francesco and Bianca, particularly their bouts of high fever, matched those of falciparium malaria, but not arsenic poisoning, which does not produce fever.
Virtually anyone working in the public eye in Italy for long may run into la polemica—violent controversy—all the more so if one’s research involves titanic figures from Italy’s storied past. The recent row over a proposed exhumation of Galileo Galilei offers a prime example of the emotions and animus that Fornaciari’s investigations can stir up. In 2009, on the 400th anniversary of the great astronomer’s first observations of heavenly bodies with a telescope, Paolo Galluzzi, director of Florence’s Museo Galileo, along with Fornaciari and a group of researchers, announced a plan to examine Galileo’s remains, buried in the basilica of Santa Croce in Florence. They aimed, among other things, to apply DNA analysis to Galileo’s bone samples, hoping to obtain clues to the eye disease that afflicted Galileo in later life. He sometimes reported seeing a halo around light sources, perhaps the result of his condition.
Understanding the source of his compromised vision could also elucidate errors he recorded. For instance, Galileo reported that Saturn featured a pronounced bulge, perhaps because his eye condition caused him to perceive the planet’s rings as a distortion. They also planned to examine Galileo’s skull and bones, and to study the two bodies buried alongside the great astronomer. One is known to be his devoted disciple Vincenzo Viviani and the other is believed, but not confirmed, to be his daughter Maria Celeste, immortalized in Dava Sobel’s Galileo’s Daughter.
Reaction to the plan was swift and thunderous. Scholars, clerics and the media accused the researchers of sensationalism and profanation. “This business of exhuming bodies, touching relics, is something to be left to believers because they belong to another mentality, which is not scientific,” editorialized Piergiorgio Odifreddi, a mathematician and historian of science, in La Repubblica, a national newspaper. “Let [Galileo] rest in peace.” The rector of Santa Croce called the plan a carnivalata, meaning a kind of carnival stunt.