The Pazzi Conspiracy: Murder in Florence Cathedral (1478)
On April 26, 1478, conspirators from the rival Pazzi family struck down Giuliano de' Medici inside Florence Cathedral during High Mass, wounding his brother Lorenzo in a failed bid to topple Medici rule. The plot, backed by powerful figures in Rome, triggered brutal reprisals across Florence and cemented the Medici grip on the city for generations. Known as the Pazzi Conspiracy, it remains one of the most notorious political assassinations of the Italian Renaissance.
A Rivalry Rooted in Banking and Power
By the 1470s, the Pazzi family had grown into one of Florence's wealthiest banking dynasties, rivaling the Medici in fortune though not in political influence. Lorenzo de' Medici, later called "the Magnificent," and his younger brother Giuliano ruled the Republic of Florence in all but name, controlling the city's institutions through patronage and alliances despite holding no formal monarchy. Tensions escalated when Pope Sixtus IV, seeking to expand papal territory for his nephew Girolamo Riario, clashed with Lorenzo over the sale of the town of Imola. The Medici bank lost its lucrative position as papal banker to the Pazzi, deepening the rift. Sixtus IV, along with Riario, Archbishop Francesco Salviati of Pisa, and disaffected Pazzi family members led by Francesco de' Pazzi, began plotting to eliminate the Medici brothers and install a government friendlier to Rome and Pazzi interests. The conspirators recruited mercenaries and clergy willing to commit violence inside a sacred space, calculating that a sudden, decisive strike during a public ceremony would prevent the Medici's armed supporters from mounting a defense. Florence itself remained a battleground of competing oligarchic families, and the Pazzi believed removing Lorenzo and Giuliano would let them seize control of the Signoria, the city's governing council, and redirect its wealth and alliances toward papal and Pazzi ambitions.
Did You Know?
The heavy bronze doors of the cathedral's sacristy, into which Lorenzo de' Medici fled to escape the assassins, had been designed by the sculptor Andrea del Verrocchio, whose workshop counted a young Leonardo da Vinci among its apprentices around that very time.
Bloodshed at the Altar
The conspirators chose Easter Sunday, April 26, 1478, and the setting of Florence Cathedral, where the Medici brothers would attend High Mass alongside much of the city's elite. The signal for attack was the ringing of the sanctus bell at the elevation of the Host. Bernardo Bandini Baroncelli and Francesco de' Pazzi fell upon Giuliano de' Medici near the altar, stabbing him repeatedly; he reportedly suffered nineteen wounds and died within moments, one blow so forceful that Francesco de' Pazzi badly gashed his own leg in the frenzy. A separate pair of assassins, including two priests, moved against Lorenzo, but their attack proved less decisive. Lorenzo suffered only a knife wound to the neck before drawing his sword, fighting his way clear, and sprinting to the sacristy, where allies sealed the massive bronze doors behind him, sealing his survival. Outside the cathedral, a simultaneous attempt to seize the Palazzo della Signoria, led by Archbishop Salviati, collapsed in confusion. News of Giuliano's murder and the attack on Lorenzo spread rapidly through Florence's streets, and rather than rising against the Medici, the populace turned violently against the conspirators, shouting support for Lorenzo and hunting down anyone connected to the plot.
Swift and Brutal Reprisal
Florentine fury proved immediate and merciless. Within hours, Archbishop Francesco Salviati and Francesco de' Pazzi were seized, and both were hanged, still in their vestments, from the windows of the Palazzo della Signoria before enraged crowds. Jacopo de' Pazzi, the family's elderly patriarch who had tried to rally support in the streets, was captured days later, tortured, and ultimately thrown into the Arno River. Bernardo Bandini Baroncelli fled abroad but was captured in Constantinople roughly a year later, extradited, and hanged in Florence; the artist Leonardo da Vinci later sketched his execution. In total, dozens of conspirators and suspected sympathizers were killed, often through mob violence, in the days following the attack. The Signoria formally banished surviving Pazzi family members from Florentine territory and confiscated their property, while officially suppressing the Pazzi name and coat-of-arms, an unusually severe punishment meant to erase the family's identity from civic life. Pope Sixtus IV, furious at the killing of the archbishop and the failure of the plot, excommunicated Lorenzo and placed Florence under interdict, then allied with the Kingdom of Naples to wage the War of the Volterra-linked conflict against the city, a struggle that dragged on until 1480. Lorenzo emerged from the crisis with his authority strengthened, ruling Florence with even firmer, more centralized control until his death in 1492.