The Pazzi Conspiracy was an attempt to assassinate the most important members of the Medici family in Renaissance Florence. The attempt occurred in 1478. It was caused by familial rivalry in Florence and by tensions between the Medici and the papacy. The attempt failed and it ended up strengthening the power of the Medici in Florence.
At this time in history, the Medici and the papacy were rivals. We have to remember that, in those times, the popes were not just spiritual leaders. They were also political leaders who controlled their own territories. Like other political leaders of the time, they wanted to expand their territories and their power. The Medici in Florence worked to try to rein in the power of the papacy because they wanted more power for their own city-state. Because of this, the pope would have been happy to get rid of the Medici.
In the Pazzi conspiracy, some church leaders (in particular, the cardinal of Pisa) conspired with the Pazzi family, which was a family of Florentine bankers who were rivals of the Medici. They planned to kill two of the most important members of the family. They attacked these two brothers in front of a huge crowd during mass on April 26, 1478. They killed one brother but the other escaped. Florentines were enraged by the attempted assassination. They killed the conspirators and forced the Pazzi family out of Florence. Thus, the conspiracy actually ended up helping the Medici consolidate their power even though it was meant to remove them.
The Pazzi Conspiracy was a plot to oust the Medici Family from their position of power in the Renaissance city-state of Florence. The Medici ruled Florence for nearly three hundred years and produced four popes. As powerful as they were, they had many enemies, including the Pazzi, Riario, and Salviati families, as well as Pope Sixtus IV (who was uncle to Giorolamo Riario). Lorenzo de Medici was a barrier to the consolidation of territory and power for the pope. While the pope could not overtly support an assassination plot, he did so tacitly.
The attack took place April 26, 1478 at the Cathedral of Florence (Duomo). Lorenzo’s brother Giuliano was stabbed to death, but Lorenzo suffered only mild wounds. The people of Florence sided firmly with the Medici rulers and the rebellion was squelched. The conspirators were pursued and killed, often lynched on the spot. (Da Vinci illustrated the lynching one of the conspirators in 1479)
This conspiracy led to a war with the papacy which was damaging to Florence in the short run. In the long run, however, the position of the Medici was strengthened: their support from the people of Florence was firm, and enemies to the Medici family were dead.