When a reconciliation had been patched up between Charles V. and Clement VII., the force of their united arms was turned against Florence. The republic was headed by gallant spirits, who, seeing their last hope of freedom in a successful resistance, exerted every nerve to defend themselves. They were willing to suffer any extremity, rather than submit to a slavery which must crush for ever the proud independence and free institutions of their native city. Guicciardini had been named by the pope, governor of Bologna, and took no part in the war against his country; but he is accused of participating in the iniquitous proceedings which followed the surrender of the city. The pope acted with the utmost treachery. He granted generous terms; but when in possession, held a mock assembly of the people, keeping off, by means of the troops he introduced, all the citizens, except those prepared to receive law at his hands. He thus, as it were, obtained a legal decree, which changed the form of government, and denounced its late leaders. Executions and confiscations became the order of the day; the chief power was placed in the hands of Vettori, Guicciardini, and two others, and their conduct entailed on them the execration of their fellow citizens.
So zealous did Guicciardini show himself, that the pope entrusted him with the office of reforming and restricting the list of candidates, who were selected to be members of government, and he displayed his prudence and sagacity for the reigning family at the expense of the lives and liberties of the most virtuous among his fellow citizens. Under his auspices, the office of gonfaloniere, which had subsisted for 250 years, was abolished, and Alessandro de' Medici was named duke, which title was to descend in perpetuity to his successors. This miserable man was the son of a negro woman, and regarded as the offspring of Lorenzo, the son of Piero de' Medici: but it was more probable that he owed his existence to Clement VII.; at least the latter claimed the honour of paternity. His disgraceful birth stamped him with contempt; his profligacy and cruelty acquired the hatred of the people over whom he ruled.
Guicciardini endeavoured to restrain him in the indulgence of his vices, but without avail. He was now wholly devoted to his service. When Clement VII. died, his successor wished him to continue governor of Bologna, but he refused. While the see was vacant, he had yielded to the entreaties of the senators, and remained to prevent popular disturbances. They promised him every assistance to maintain his authority; but his enemies took occasion to display their disrespect. Geronimo Pepoli, and others, who some years before had retired from Bologna in distaste, took this occasion to return, accompanied by armed followers and public bandits. Guicciardini's haughty spirit was in arms against the insult. Among the followers of Pepoli were two outlaws under sentence of death; these he caused to be seized, led to prison, and put to death. Pepoli manifested the utmost indignation, and was only restrained by the authority of the senators from giving public token of his resentment. When the new pope was elected, and another governor appointed, Guicciardini prepared to quit the city. Pepoli threatened to attack him on his departure; but he, undismayed, set out at noon-day, accompanied only by a few attendants on horseback. His road led him past the palace of the Pepoli, nor would he diverge from it on this account, but passed under their windows with a firm and intrepid countenance, and was permitted to pursue his way unmolested.