(April 16, 1478) Unsuccessful plot to overthrow the Medici rulers of Florence. It was led by the rival Pazzi family, with the backing of Pope Sixtus IV, who wanted to consolidate papal rule over northern central Italy. The conspirators tried to assassinate two Medici brothers during mass at the Cathedral of Florence; they killed Giuliano de' Medici, but Lorenzo de' Medici escaped. The people of Florence rallied to the Medici and killed many of the conspirators, leaving Lorenzo more powerful than before and setting off a two-year war with the papacy.
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The Pazzi family were Tuscan nobles who were bankers in Florence in the 14th century. They are now best known for the "Pazzi conspiracy" to assassinate Lorenzo de' Medici and Giuliano de' Medici on April 26, 1478. Andrea de' Pazzi was also the patron for Filippo Brunelleschi's chapter house for the Franciscan community at Florence's Santa Croce church, often known as the Pazzi Chapel. After the conspiracy, the Pazzi were rehabilitated and returned to Florence.
The family stemmed from Pazzo ("the madman"), one of the first soldiers over the walls in the Siege of Jerusalem during the First Crusade, who brought away with him and returned to Florence a stone from the Basilica of the Holy Sepulchre. A member of the Pazzi family was accorded the privilege of striking a light from this stone on Holy Saturday when all fires in the city were extinguished, from which the altar light of the Duomo would be annually rekindled, and from it all the hearth fires of Florence. The following day, Easter, a dove-shaped rocket would slide on a wire from above the high altar to an oxcart loaded with fireworks in the piazza. From the fireworks' explosion (the scoppio del carro), sparks would be carried to the city's hearths.
Lesser rivals of the Medici, the Pazzi were caught up in a conspiracy to replace the Medici as de facto rulers of Tuscany with Girolamo Riario, a nephew of Francesco della Rovere, who was reigning as Pope Sixtus IV. Power politics, often ruthless in the Italian Renaissance, were the main motive.
The Pazzi family were not the instigators. The Salviati, Papal bankers in Florence, were at the center of the conspiracy. Sixtus was an enemy of the Medici. He had purchased the lordship of Imola, a stronghold on the border between Papal and Tuscan territory that Lorenzo wanted for Florence. The purchase was financed by the Pazzi bank, even though Francesco dei Pazzi had promised Lorenzo they would not aid the Pope. As a reward, Sixtus granted the Pazzi monopoly at the alum mines at Tolfa — alum being an essential mordant in dyeing in the textile trade that was central to the Florentine economy — and he assigned to the Pazzi bank lucrative rights to manage Papal revenues. Sixtus appointed his nephew Girolamo Riario as the new governor of Imola, and Francesco Salviati as archbishop of Pisa, a city that was a former commercial rival but now subject to Florence. Lorenzo ordered Pisa to exclude Salviati from his See.
Salviati and Francesco de' Pazzi put together a plan to assassinate Lorenzo and Giuliano de' Medici. Riario himself remained in Rome. The plan was widely known: the Pope was reported to have said, "I support it — as long as no one is killed." In 2004, an encrypted letter in the archives of the Ubaldini family was discovered by Marcello Simonetta, a historian at Wesleyan University in Connecticut, and decoded. It revealed that Federico da Montefeltro, Duke of Urbino, a condottiere for the Papacy who was deeply embroiled in the conspiracy, committed himself to position 600 troops outside Florence, waiting for the moment.
On Sunday, April 26, 1478, during High Mass at the Duomo before a crowd of 10,000, Giuliano de' Medici was stabbed 19 times by a gang that included a priest. As he bled to death on the cathedral floor, his brother Lorenzo escaped with serious, but non life-threatening wounds. Lorenzo appeared shortly after, locked safely in the sacristy by the humanist Poliziano. A coordinated attempt to capture the Gonfaloniere and Signoria was thwarted when the archbishop and head of the Salviati clan were trapped in a room whose doors had a hidden latch. The coup d'état failed, and the enraged Florentines seized and killed the conspirators. Jacopo de' Pazzi was tossed from a window. To finish him off, the mob dragged him naked through the streets, then threw him into the Arno River. The Pazzi family were stripped of their possessions in Florence, every vestige of their name effaced. Salviati was hanged on the walls of the Palazzo della Signoria. Although Lorenzo appealed to the crowd not to exact summary justice, many of the conspirators, as well as many people accused of being conspirators, were killed. Lorenzo did manage to save the nephew of Sixtus IV, Cardinal Raffaele Riario, who was almost certainly an innocent dupe of the conspirators, as well as two relatives of the conspirators. The main conspirators were hunted down throughout Italy; however, a wider retribution by Lorenzo, including hundreds of killings, is a myth.
In the actual aftermath of the so-called "Pazzi" conspiracy, the Della Rovere Pope placed Florence under interdict, forbidding Mass and communion, for the execution of the Salviati archbishop. Sixtus enlisted the traditional Papal military arm, the King of Naples, Ferdinand I, to attack Florence. With no help coming from Florence's traditional allies in Bologna and Milan, only Lorenzo's diplomacy saved the day. He sailed to Naples and put himself in the hands of Don Ferrante, who held him captive for three months before releasing him with gifts. Lorenzo's courage and his Machiavellian realpolitik showed Don Ferrante that the Pope would turn against him if he were too successful in the North.
On another level, perhaps the greater mark on history left by the Pazzi is the Pazzi Chapel built under the direction of Filippo Brunelleschi in a discreet cloister of the Franciscan church, Santa Croce. After some early agreements, the chapel was begun in 1442. It is one of the incunabula of Renaissance architecture: severely restrained, made of pietra serena and white plaster, and unrelieved by color. A hemispherical dome (completed after Brunelleschi's death following his plans) caps a cubical sacristy for the Franciscan church: within it the Pazzi family were permitted to bury their dead.
The main seat of the family, at canto Pazzi, where Borgo degli Albizi crosses the via del Proconsolo was rebuilt 1462–1472 for Jacopo de' Pazzi to designs by Giuliano da Maiano, the sculptor-architect favored by the family. Above its wholly traditional rusticated ground floor of the yellow-ochre sandstone Florentines call pietra forte it has a stuccoed facade in a new taste, with delicate designs round the windows in the manner associated with Brunelleschi. The central court is surrounded on three sides by round-headed arcading, with circular bosses in the spandrels.
Next to it is the smaller 16th-century three-story Palazzo Pazzi-Ammannati, rebuilt for Antonio Ramirez di Montalvo, housing Florence's small museum of natural history and host to temporary exhibitions. Its design is attributed to Bartolomeo Ammanati.
Thomas Harris's 1999 novel Hannibal features a character named Rinaldo Pazzi, a corrupt policeman descended from the Pazzi family. He is murdered and disemboweled by Hannibal Lecter, and then hungs the balcony of the Palazzo della Signoria, just as his famous "ancestor" was. In the 2001 film adaptation, he is played by Giancarlo Giannini.
A fictionalized version of the Pazzi conspiracy was the basis for the DC Comics Elseworlds story "Black Masterpiece," in Batman Annual #18, which features a Renaissance-era Batman and Leonardo da Vinci.
The Pazzi Conspiracy is the foundation for the book I, Mona Lisa, by Jeanne Kalogridis.
Primavera, a YA novel by Mary Jane Beaufrand, tells the story of the Pazzi Conspiracy from the point of view of the youngest Pazzi daughter, Flora.