Pazzi Conspiracy (1478): Murder in Florence Cathedral

The Pazzi Conspiracy was an attempt to murder Lorenzo and Giuliano de’ Medici, the brothers who dominated Florence, during High Mass in the city’s cathedral on 26 April 1478. Giuliano was stabbed to death in front of the altar, but Lorenzo escaped wounded, and the coup collapsed within hours. The plot, backed by Pope Sixtus IV, ended in public executions, a war with the Papacy and Naples, and a Medici regime that emerged stronger than before.

Background: Florence, the Medici and their rivals

In the fifteenth century Florence was formally a republic governed by elected councils and a nine-man executive, the Signoria. In practice, from 1434 it was steered by the Medici family, whose wealth came from the Medici Bank. Cosimo de’ Medici, then his son Piero, and from 1469 his grandsons Lorenzo (born 1449) and Giuliano (born 1453) controlled who held office without holding a crown.

The Pazzi were an older and equally proud banking family. Relations with the Medici had been workable, but they soured in the 1470s. Lorenzo blocked Pazzi marriages and inheritances that would have increased their influence, and the Pazzi came to resent being shut out of the highest offices.

The decisive tensions came from Rome. Pope Sixtus IV, elected in 1471, wanted to build a state in central Italy for his nephew Girolamo Riario. In 1473 he arranged to buy the town of Imola for Riario. Lorenzo, who wanted Imola within Florence’s sphere, tried to stop the Medici Bank lending the money; the Pazzi bank lent it instead. Sixtus then moved the lucrative papal accounts away from the Medici. When the Pope appointed Francesco Salviati, an ally of the Pazzi, as Archbishop of Pisa in 1474, Lorenzo for a time refused to let him take up the see.

The plotters and the plan

The conspiracy brought together three groups with different aims. Francesco de’ Pazzi, who managed the family bank in Rome, wanted to replace the Medici. Girolamo Riario wanted a friendly government in Florence to protect his new lordship. Archbishop Salviati wanted his see and greater power. The head of the Pazzi family, the elderly Jacopo de’ Pazzi, was at first reluctant but joined.

A professional soldier, Giovan Battista da Montesecco, was recruited to do the killing. According to his later confession, he and the plotters met Sixtus IV, who said he wanted a change of government in Florence but no deaths, while making clear he would protect those involved. Ferrante, King of Naples, also backed the scheme. Research published in the 2000s by historian Marcello Simonetta showed that Federico da Montefeltro, Duke of Urbino, had secretly promised troops.

The plan required both brothers to be killed at the same moment. Attempts to arrange a banquet failed, and the plotters chose Sunday Mass in the cathedral, celebrated in honour of the young Cardinal Raffaele Riario, the Pope’s great-nephew, who was visiting Florence. Montesecco refused to shed blood in a church, so two priests, Antonio Maffei of Volterra and Stefano da Bagnone, were given the task of killing Lorenzo.

What happened on 26 April 1478

Giuliano, unwell that morning, was late, and Francesco de’ Pazzi and Bernardo Bandini Baroncelli went to fetch him. During the Mass beneath Brunelleschi’s dome, at a pre-arranged moment, Bandini struck Giuliano and Francesco de’ Pazzi stabbed him repeatedly; contemporary accounts speak of some nineteen wounds. Francesco attacked so wildly that he wounded his own thigh.

The two priests were less skilled. One grabbed Lorenzo’s shoulder and cut his neck, but Lorenzo drew his sword, fought free and leapt over the choir rail. Francesco Nori, a Medici bank manager, was killed shielding him. Lorenzo and his friends, including the poet Angelo Poliziano, took refuge in the north sacristy and barred its heavy bronze doors.

Meanwhile Archbishop Salviati and a band of armed men went to the Palazzo della Signoria, claiming to bring a message from the Pope. The Gonfalonier of Justice, Cesare Petrucci, became suspicious, and the intruders were trapped when doors locked behind them. When Jacopo de’ Pazzi rode into the square with horsemen crying “Popolo e libertà” (people and liberty), the citizens answered with the Medici rallying cry “Palle, palle”, after the balls on the family’s coat of arms. The coup had failed.

The reprisals

Revenge was immediate and brutal. Francesco de’ Pazzi, dragged from his bed, and Archbishop Salviati were hanged from the windows of the Palazzo della Signoria that same evening. Jacopo de’ Pazzi fled, was captured in the countryside and executed; his body was later dug up, dragged through the streets and thrown into the Arno. The two priests were found and killed, and Montesecco was beheaded after giving his confession.

Estimates suggest that around 80 people died in the days and weeks that followed, some of them only loosely connected to the plot. The Pazzi name and coat of arms were ordered erased, surviving members were imprisoned or exiled, and Pazzi women were forbidden to marry. Bernardo Bandini escaped to Constantinople, but Sultan Mehmed II handed him back, and he was hanged in Florence in December 1479. A sketch of his hanging body by the young Leonardo da Vinci survives.

Effigies of the hanged conspirators were painted on a public wall in the city centre, a traditional Florentine form of shame; Sandro Botticelli received the commission. Lorenzo also had commemorative medals cast by Bertoldo di Giovanni showing the attack in the cathedral.

The war with Rome and Naples

Sixtus IV reacted to the execution of an archbishop with fury. In June 1478 he excommunicated Lorenzo and the government of Florence and placed the city under an interdict, a ban on most church services. Naples and the Papacy went to war with Florence, and their armies, led in part by Federico da Montefeltro, ravaged Florentine territory.

By late 1479 the war was going badly. In December Lorenzo sailed to Naples to negotiate in person with King Ferrante, a famous gamble since he had no guarantee of safe return. He secured peace in early 1480, and Sixtus accepted a settlement later that year. Lorenzo returned with his authority enhanced.

Consequences and legacy

The conspiracy failed in its main aim and had the opposite effect. Florentines rallied to the Medici, and in 1480 Lorenzo created a new Council of Seventy that tightened his control over the state. He governed until his death in 1492 and became known as “il Magnifico”.

Giuliano left an illegitimate son, Giulio, born weeks after his death and raised by Lorenzo. He later became Pope Clement VII (1523–1534). The episode also left a lasting picture of Renaissance politics as a mix of high culture, family rivalry and religious authority used for worldly ends, a theme taken up by writers from Niccolò Machiavelli, who described the plot in his Florentine Histories, to modern novelists.

Two years after Lorenzo’s death the Medici were expelled from Florence, and the preacher Girolamo Savonarola rose to dominate the city, culminating in the Bonfire of the Vanities.

Timeline

• 1473: Sixtus IV buys Imola for Girolamo Riario with a loan from the Pazzi bank.
• 1474: Francesco Salviati is made Archbishop of Pisa; Lorenzo opposes his appointment.
• 1477–1478: The conspiracy is planned in Rome and Florence.
• 1478, 26 April: Giuliano de’ Medici is killed in the cathedral; the attempt to seize the Palazzo della Signoria fails.
• 1478, 26–28 April: Francesco de’ Pazzi, Archbishop Salviati and Jacopo de’ Pazzi are executed.
• 1478, June: Sixtus IV excommunicates Lorenzo and places Florence under interdict; war follows.
• 1479, December: Bernardo Bandini is hanged in Florence; Lorenzo travels to Naples.
• 1480: Peace with Naples and a settlement with the Pope.

Why it matters

The Pazzi Conspiracy is one of the most dramatic episodes of the Italian Renaissance. It showed how far rival families and even a pope would go to control a rich city, and its failure consolidated the Medici, whose patronage shaped Florentine art and later produced two popes and the grand dukes of Tuscany.