Keep pulling the thread on Ada Palmer.
Pope Sixtus IV organized the Pazzi conspiracy in an attempt to assassinate the Medici family, which resulted in the death of Lorenzo de' Medici's brother, and to stage a coup to take control of Florence.
The Republic of Florence's diplomatic strategy towards Cesare Borgia, as advised by Niccolò Machiavelli, was to buy time by offering total submission, including military forces and money, and breaking its 300-year alliance with Bologna.
The Republic of Florence's standard foreign policy tactic was to bribe potential invaders, such as Maximilian I of the Holy Roman Empire, rather than engage them in direct military conflict.
Due to long-standing political factions in Renaissance Italy, there were instances of war between Rome and Florence where Florence fought to defend the abstract authority of the Papacy against the actions of the sitting Pope.
After conquering cities in central Italy and massacring the ruling families, Cesare Borgia became popular with the common people because he implemented a system of neutral justice.
Ada Palmer asserts that had Pope Alexander VI lived for one more year, Cesare Borgia would have completed his conquests and successfully taken over the Republic of Florence.
Cesare Borgia executed some of his own men who were plotting against him at a banquet in Senigallia after first feigning forgiveness and renewing vows of loyalty.
According to Ada Palmer, Cesare Borgia's kingdom collapsed not due to his political methods but because of his own illness, the premature death of his papal ally Pius III, and being outmaneuvered by his rival, Julius II.
The city of Florence previously resolved internal political factionalism by massacring the Ghibellines, killing all of them, and salting the earth where their houses stood so nothing could grow there again.
In the period leading up to Machiavelli's writing of "The Prince", a series of consecutive Popes expanded their executive and military power, frequently launching wars and arbitrarily overthrowing the governments of city-states under Papal rule.
The electoral nature of the Papacy created political instability in Renaissance Italy, as a new Pope was typically elected every 10 years by a coalition opposed to the previous one, leading to a reversal of the predecessor's policies.
The city-states of Renaissance Italy, particularly Florence, used art and cultural patronage as a form of diplomacy and soft power, which was a more cost-effective defense strategy against larger powers like France than direct military spending.