Sixtus made overtures to the Duke of Milan to detach him from the
alliance, but, apparently, they failed of their object. The Duke was
friendly with Lorenzo and had no wish to become embroiled with Florence.

All these plots and counterplots were exactly to the liking of Francesco
de' Pazzi, and he laid himself out to make capital out of them. Not only
did he encourage the Pope in his inimical policy, but he placed at his
command the sum of money which had been refused by the Medici bank.
Sixtus was delighted with his new and wealthy adherent, and forthwith
gave the presidents of the Medici bank in Rome notice that they no
longer retained his confidence as Papal bankers, and that, accordingly,
he had transferred the accounts of the Curia to the care of the rival
Pazzi house. Upon Francesco de' Pazzi he conferred the accolade of
knighthood. This hostile action of course further estranged Lorenzo and
the Government of Florence, and, quite naturally, a system of
quarrelsome incidents was set up, with a very complete equipment of
spies.

Sixtus never concealed his desire for the overthrow of Lorenzo and the
subversion of the Florentine Government, and his hostility found a
whole-hearted response in the persons of Count Girolamo de' Riari,
Archbishop Francesco de' Salviati, and Cavaliere Francesco de' Pazzi.
The Pope exulted openly in what capital he could make out of tales and
gossip about Lorenzo and his entourage. Two prominent Florentines
fomented this factious spirit. Giovanni Neroni--the Archbishop of
Florence in succession to Archbishop d'Orsini, brother of the notorious
Diotisalvi, who was banished in 1466--and Agnolo Acciaiuolo--also
banished the same year, who resided in Rome and was an especial
favourite at the Vatican.