In 1354, Giannino di Guccio, a merchant aged thirty-eight with a wife and children, went to Rome and received a shocking revelation from Cola di Rienzo, a Roman senator. Cola told Giannino that he was the proper and rightful king of France, for he was the son of King Louis and Queen Clémence, and was exchanged for another a few days after his birth. At the time, the kingdom of France was being torn apart by a conflict that would later be called the Hundred Years' War. It was caused by the fact that the king of England and the king of France each regarded themselves as the legitimate heir of the Capetian crown. If Giannino di Guccio was really Jean I of France, in other words the firstborn male child of the eldest son of Philippe the Fair, then he ranked higher than either of the two kings as successor to the throne. He returned to Siena, bringing with him a pair of magnificent horses, a defective seal, and two letters patent from Cola di Rienzo.
Keywords: Giannino di Guccio, Cola di Rienzo, Rome, France, England, Hundred Years' War, Jean I, King Louis, Queen Clémence, king