The conspirators and their issues:
One of the main players behind the conspiracy was the avaricious Pope Sixtus IV*. He felt great hostility towards the Medici.
The pope wanted to add Florence and its territories to his Papal States, thus considerably increasing the size of his holdings and his income, while upsetting the delicate balance of power in central Italy. He also needed money to finance several major construction projects in Rome, including the creation of the Vatican Library. From Florence he would have leverage to pressure cities in the nearby Romagna, and by taking them create a kingdom for his nephew, Girolamo Riario. All of this would add to the pope’s expanding power base. But Lorenzo resisted.
When the pope asked Lorenzo to lend him money to finance his military campaigns in the Romagna, Lorenzo refused to commit any support. Instead, to strengthen their bonds with Rome, the Pazzi,a rival Florentine banking family, loaned 30,000 ducats to the pope. This angered Lorenzo, who encouraged the other Florentine bankers to hold onto their money.
The pope then changed bankers: he shifted the administration of the papal finances from the Medici to the Pazzi. This created a deep rift between Rome and the Medici. Managing the papal finances paid large commissions, creating enormous wealth for the managers: the Medici lost a major source of income.
The pope also ordered an audit on the accounts of the alum mine trade, also managed by the Medici. Alum was central the the dyeing trade in Florence, so a major source of revenue. The Pope granted the Pazzi the monopoly on the alum.
Then, Lorenzo passed a law retroactively prohibiting family inheritance by female offspring. The death of the wealthy Pazzi elder, Giovanni Borromei, without male heirs, meant that the Pazzi assets passed to the cousins, not to his wife, Beatrice. This dealt a blow to the Pazzi fortunes and exacerbated tensions between the families.
The pope was well aware of the plot and supported it, although he did not commit any of his troops to it.
Francesco Salviati was a member of a less distinguished, but still powerful Florentine family, who acted as Papal bankers in the city. Francesco had taken holy orders and was a bishop in the 1470s. He wanted to become archbishop of Florence, his home city, and the pope agreed. But the Medici made sure the position went to Rinaldo Orsini, the brother of Lorenzo’s new wife (the Orsini were another powerful family in Italy).
Francesco turned to Pope Sixtus for help. The pope didn’t have control over the appointment, but instead named Salviati archbishop of Pisa, a client city-state of Florence. This was an insult to both the Medici and the city of Florence because in the past, popes had always consulted with the city when selection an archbishop for Pisa. This infuriated Lorenzo so much that he ordered the gates of Pisa closed, preventing Salviati from entering to take office. Francesco was forced to bide his time in Rome, fretting and plotting, until Lorenzo relented in 1475.
Federigo da Montefeltro, Duke of Urbino (right), was a mercenary – a conditierre – who was playing for personal gain and an easy profit by renting out his troops to the pope. His daughter was married to Giovanni Della Rovere, the pope’s favourite nephew, and his title had been granted by the pope in 1474. He secretly committed to put 600 of his troops outside Florence to support the conspirators. **
King Ferrante of Naples was a silent partner in the conspiracy, but with long-range goals to gain from the events. He had ambitions to extend his kingdom north, outflanking the papal states and Florence was a serious obstacle. He needed to unseat the Medici and replace them with a family or ruler more supportive of his cause. He agreed to supply his army to aid the pope. Later, he made peace with Lorenzo, which angered the pope.
Girolamo Riario was a favourite nephew of Sixtus IV. The pope purchased the stronghold of Imola, from Milan, but the Medici had wanted it for Florence. The pope gave it to his nephew as a dowry when he married Caterina Sforza (daughter of Galeazzo Maria Sforza, Duke of Milan) in 1473. Although Girolamo survived the aftermath for many years, he continued to plot against the Medici, but all his efforts failed. In 1488 he was assassinated – the last of the main Pazzi conspirators alive – by members of the Orsi.
Continued in Part 3
* Wikipedia notes:
One of his first acts was to declare a renewed crusade against the Ottoman Turks in Smyrna. Fund-raising for the crusade was more successful than the half-hearted attempts to storm Smyrna, with little to show in return.
This ill-considered crusade would later come back to haunt Sixtus during the aftermath of the Pazzi conspiracy. In the middle of their march on Florence, Naples had to shift its attention away from the conflict to southern Italy to deal with a Turkish invasion. In 1480, an army from the the Ottoman Empire landed at Otranto, under orders to march on Rome and capture the city. After a two-week battle they captured Otranto, then massacred the inhabitants. The pope panicked, and demanded King Ferdinand of Naples gather together a new crusade to defeat the Turks. The Turkish ruler, Mehmet the Conqueror, sailed to Italy to lead the army on to conquer the rest of the peninsula, but died en route. His successor ordered the army’s general to be hung, and the Turks retreated at the end of September, 1481. Ferdinand’s son Alphonso, duke of Calabria, retook the city after 13 months of Turkish rule.
** In 1482, when the pope turned against other Italian republics, Ferdinand switched sides. He joined the city states of Ferrara and Milan against the alliance of Sixtus IV and the Republic of Venice.