Ferdinando I de’ Medici promoted extraordinary religious tolerance in the Grand Duchy of Tuscany during his reign. His Livornine laws of 1591 and 1593 granted Jews in Pisa and Livorno broad freedoms, rare in sixteenth-century Europe. Newly uncovered archival documents reveal how Ferdinando consistently defied the papacy in defense of his Jewish subjects. This article examines Ferdinando’s efforts on behalf of one Jewish merchant named Jacob Esperiel. Ferdinando went to great lengths to protect Esperiel and his family from the Roman Inquisition, yet he was not the first Medici to have a favorable policy toward Jews. Motivated by mercantilism and ragione di stato, the family had welcomed the Jewish community in Florence during the Renaissance. Moreover, this pattern of tolerance endured beyond the Medici; eventually the Grand Duchy of Tuscany would break new ground in human rights as the first European state to ban capital punishment in 1786.