There’s no evidence that Machiavelli witnessed any killings himself, but it seems unlikely that in a city the size of Florence he would have been able to avoid seeing either the street violence or its aftermath. At the time, Machiavelli lived just across the Ponte Vecchio, a two minute walk from the Palazzo Vecchio. Lauro Martines calls Machiavelli’s account of the events “fanciful,” which may be true, but it seems clear that the chaos following the failed assassination made a significant impression on him.
For more information on the Pazzi Conspiracy, read Machiavelli’s account in the Istorie Fiorentine. As I mentioned, Machiavelli’s account contains some inaccuracies, whether intentional or not is unclear. For a more modern take, Martines’ April Blood is good, as is Marcello Simonetta’s The Montefeltro Conspiracy, which uses exciting new evidence in an attempt to show that the Pazzi were not the prime movers of the conspiracy, but that the Duke of Urbino—Federico da Montefeltro—had an even greater hand in the planning.
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