It has been already observed, that from the tenor of Poggio’s answer to the complimentary letter of the duke of Milan, he appears not to have given implicit credit to that prince’s professions of friendship for the Florentine republic, and that he evidently expected that the restless ambition of Filippo would again kindle the flames of war. Events justified his prognostications. In the year 1439, the administrators of the Tuscan government were so much alarmed by the success of Piccinino, who had invaded the Venetian territories at the head of the Milanese army, that they renewed their alliance with their ancient friends, to whose assistance they sent a considerable body of troops, under the command of Francesco Sforza. The duke of Milan, with the view of compelling the Tuscans to withdraw their forces from Lombardy, directed Piccinino to make an incursion into the territories of Florence. Piccinino accordingly marched through Romagna, and made himself master of several places in the district of Casentino. The duke of Milan expected to have derived considerable assistance in the invasion of the Tuscan territories from Vitelleschi, with whom he had for some time carried on a secret correspondence, and who had, through hatred of the Florentines, engaged to support Piccinino with a powerful body of troops. But the secrecy with which this intrigue had been conducted did not elude the vigilance of the administrators of the Tuscan government. They fortunately intercepted certain letters addressed by the duke to Vitelleschi, which revealed the particulars of the conspiracy. These letters they communicated to the pontiff, who gave immediate orders for the arrest of the perfidious patriarch. As Vitelleschi was then at Rome, the execution of this commission was entrusted to Antonio Rido, the commandant of the castle of St. Angelo. According to the instructions of Eugenius, Vitelleschi was suddenly surrounded by a troop of horse, as he was passing the bridge of St. Angelo, on his way to join the forces which he had destined for the assistance of Piccinino. He was no sooner aware of his danger, than he boldly drew his sword, and endeavoured to cut his way through the soldiers who were sent to secure him. In the conflict he was wounded in the neck, and growing faint with loss of blood, he was overpowered and carried as a prisoner into the castle. On the twentieth day of his confinement he died, as some say of his wounds, according to the report of others, of poison. By whatever means he came to his end, so atrocious were the cruelties which he had committed during the days of his power, that his death occasioned universal joy, and was regarded by thousands as a signal instance of divine retribution.[337]