A capitulation was arranged whereby Varano engaged to give up the town, on condition that he and his sons were allowed to retire safe and sound, taking with them their furniture, treasure, and carriages.

But this was by no means Caesar's intention; so, profiting by the relaxation in vigilance that had naturally come about in the garrison when the news of the capitulation had been announced, he surprised the town in the night preceding the surrender, and seized Caesar di Varano and his two sons, who were strangled a short time after, the father at La Pergola and the sons at Pesaro, by Don Michele Correglio, who, though he had left the position of sbirro for that of a captain, every now and then returned to his first business.
Meanwhile Vitellozzo Vitelli, who had assumed the title of General of the Church, and had under him 800 men-at-arms and 3,000 infantry, was following the secret instructions that he had received from Caesar by word of mouth, and was carrying forward that system of invasion which was to encircle Florence in a network of iron, and in the end make her defence an impossibility.

A worthy pupil of his master, in whose school he had learned to use in turn the cunning of a fox and the strength of a lion, he had established an understanding between himself and certain young gentlemen of Arezzo to get that town delivered into his hands.

But the plot had been discovered by Guglielma dei Pazzi, commissary of the Florentine Republic, and he had arrested two of the conspirators, whereupon the others, who were much more numerous than was supposed; had instantly dispersed about the town summoning the citizens to arms.

All the republican faction, who saw in any sort of revolution the means of subjugating Florence, joined their party, set the captives at liberty, and seized Guglielmo; then proclaiming the establishment of the ancient constitution, they besieged the citadel, whither Cosimo dei Pazzi, Bishop of Arezzo, the son of Guglielmo, had fled for refuge; he, finding himself invested on every side, sent a messenger in hot haste to Florence to ask for help.
Unfortunately for the cardinal, Vitellozzo's troops were nearer to the besiegers than were the soldiers of the most serene republic to the besieged, and instead of help--the whole army of the enemy came down upon him.