The king had a personal quarrel with Lorenzo, because he had married Clarice d’Orsini in preference to his daughter, whose hand he had, in a way, offered to the young prince.  He at once acceded to the Pope’s invitation, and, as good as his word, he despatched his son, the Duke of Calabria, at the head of an armed force, professedly to demand prompt payment by the Republic of arrears due to him for service rendered to Florence.

At the solicitation of Sixtus these troops were retained in Tuscany on the pretext that the Papal fief of Imola required protection.  Of course the real purpose was a menace to Lorenzo:  the force being at hand to strike a swift blow when necessary.

Duke Federigo of Urbino was made more or less conversant with the Papal policy, and with the special question of Lorenzo’s removal.  He at once rejected the proposition that resort should be had to violent or secret measures, and in disgust at Sixtus’s conduct, he threw up his appointment as Commander of the Papal forces.

Whilst Sixtus was making all these military preparations for the furtherance of his intentions, his co-conspirators removed the scene of their activities to the neighbourhood of Florence, where the Pazzi and Salviati were at one in their readiness to lay down their lives for the undoing of the Medici.  They first of all took into their confidence one of the Papal Condottieri, a man of undoubted courage and ability—­Giovanni Battista da Montesicco, a native of the Roman Campagna—­who was under heavy obligation to Count Girolamo de’ Riari.  Of course he was perfectly willing, as became his calling, to sell his sword for good payment:  he further undertook to enlist his lieutenant, Hieronimo Comiti, in the cause.

The Condottiere was sent off to Florence to communicate to Cavaliere Giacopo de’ Pazzi the “idea” of the three chief plotters, to test his feelings, and, if possible, secure his adherence.  At first the old man was “as cold as ice”—­so Montesicco said in his confession later on—­and declined to take any part in the conspiracy.  After hearing all that was put before him, he enquired whether Sixtus approved the scheme.

“Why, his Holiness,” replied the Condottiere, “has sent me straight to your Honour to ask your support....  I speak for the Pope.”

“Then,” said Giacopo, “I am with you.”

A few days later Archbishop Salviati and Francesco de’ Pazzi joined Montesicco at Giacopo’s country villa, at Montughi, just beyond the Porta Rosso, on the high road to Bologna.  Consultations between the heads of the two families, Pazzi and Salviati—­were held there, with the concurrence of a certain number of influential citizens inimical to the Medici.

These meetings were given out as hunting-parties and, to blind their eyes, overtures were made to both Lorenzo and Giuliano to honour the sport with their presence.  Needless to say, Francesco de’ Pazzi’s return to Florence, in company with the unfriendly Archbishop, aroused Lorenzo’s suspicions, but he does not appear to have taken any action.