With the encouragement of Pope Sixtus IV (better known in posterity for the Sistine chapel), the Pazzi and Salviati families attempt to assassinate the de facto ruler of Florence Lorenzo de’ Medici later known as Il Magnifico and his brother Guiliano in church during high mass. Guiliano was stabbed 19 times and bled to death on the floor. Lorenzo was wounded but escaped.
The infuriated Florentine mob then took brutal vengeance on the conspirators. Jacopo de’ Pazzi was tossed from a window and to make sure the job was done, the mob dragged him naked through the streets before tossing him into the Arno River. Archbishop Salviati of Pisa another conspirator was hanged on the walls of the Palazzo Vecchio. The Pazzi family lost all their Florentine posessions and suffered in effect a damnatio memoriae. Other conspirators were hunted down all over Europe.
The pissed off Pope used the lynching of the Archbishop as an excuse to excommunicate Lorenzo and place Florence under an interdict. He then encouraged his ally King Ferrante of Naples to attack Florence. Facing imminent doom Lorenzo sailed to Naples and put himself at the mercy of King Ferrante and through personal charisma and the evidence of his bravery convinced the King to attempt broker a peace treaty with the still fuming Pope. The end result of the Papal backed plot was the consolidation of Medici control over Florence and the further diminution of Papal prestige.
Medici control over Florence would end abruptly after Lorenzo’s death as his incompetent son Piero the unfortunate could not manage the tidal waves created by the French invasions of Italy in the 1490s. The Medici would oscillate in and out of power for two decades until their good fortune in having two Popes in the family – Lorenzo’s son Leo X soon to be followed by Guilano’s bastard son Clement VII allowed the Medici to return as hereditary Dukes of Florence in 1532 (upgraded to Grand Dukes of Tuscany in 1569). The House of Medici ended with the death of the melancholy, decrepit Gian Gastone de’ Medici in 1737.