The power of the Medici was odious in that city. A formidable party, whose watchword was liberty, regarded with triumph the dangers to which Clement VII. was exposed. A number of the younger nobility among them took occasion of the alarm excited, to seize on the palace of government. The duke of Urbino prepared to attack it, but first sent Federigo da Bozzole to treat with the party who held it. Full of enthusiasm and courage, the young men refused all terms, and Bozzole left them, enraged at their obstinacy and their personal ill-treatment of himself. Guicciardini perceived the dangers that threatened his country. It was an easy task for the duke of Urbino to attack the palace of government, to destroy it and all those within; but an act of violence and bloodshed was to be avoided. Guicciardini hastened forward to meet Bozzole as he left the palace, and represented to him briefly how displeasing such a contest would be to the pope, and how detrimental to the confederates; and how much better it would be to calm, instead of exasperating, the mind of the duke of Urbino. Bozzole yielded, and gave hope to the duke that quiet might be restored without recourse being had to arms; pacific means were in consequence resorted to, and the insurgents induced to quit the palace. Guicciardini relates this circumstance and his interference with pride, in the belief that he had done his country as well as the pope good service, but he adds, that he got no thanks from either side; the Medici party accusing him of preferring the lives and safety of the citizens to the firm establishment of that family; while the other party declared that he had exaggerated their difficulties, and caused them needlessly to yield their advantages.

It had been well for the fame of Guicciardini, if he had submitted to the blame of his contemporaries, and secured the approbation of posterity, by adhering to a line of conduct so impartial and patriotic. Although the fall of the Medici was suspended for a short time on this occasion, the taking of Rome decided their expulsion. When the duke of Urbino went southward to deliver the pope, besieged in the Castel Sant' Angelo, the Florentines seized the opportunity to drive out the Medici, and to restore the freedom of their government. The wars carried on by Clement VII. had weighed heavily on the republic, since he drew from it his chief resources; the people were thus exasperated against his rule, and now that they possessed the power, displayed their hatred of his family by many acts of outrage. To have served them was to share their disgrace, and the odium with which they were regarded. It has been related how Machiavelli, republican as he was, and personally attached to many of the leaders of the popular party, was unable to overcome the prejudice excited by his having entered the service of the Medici. Guicciardini was visited by more open marks of the dislike of the new leaders; and he was the more angry because he had displayed a wish to join them. He neither loved nor esteemed Clement; whom he represents as timid; avaricious, and ungracious. He regarded his imprisonment by the imperialists with very lukewarm interest, and even raised soldiers for the defence of Florence: but these demonstrations did not avail to acquire for him the confidence of his countrymen, and he was forced to fly the town during a popular tumult. Hence seems to spring his hatred of free institutions, and his subsequent conduct in aiding in the destruction of the liberties of his country. From this time he entered with all the zeal of personal resentment into the cause of the Medici. His name has thus received a taint never to be effaced. He became the abettor of tyrants, the oppressor of his fellow citizens; and that equity and firmness which he before exercised; by establishing order in the districts over which he presided, were changed to the persecution of the martyrs of liberty.[33] It is impossible to slur over this portion of his life as he does himself. For it is remarkable that the only events recorded in his history, which are narrated in a slovenly and confused manner, are those in which he took a principal share,—the second restoration of the Medici, and the final overthrow of the liberties of Florence.

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.

He soon after displayed this energy and firmness of character in a very bad cause. The Florentines, unable any longer to endure the tyranny and vices of duke Alexander, appealed to Charles V., whom they regarded as lord paramount of their state. The emperor summoned Alexander to Naples, where he then was, to answer the charges made against him. He obeyed: but the emperor was so incensed that he began to fear the result, and was on the point of retreating, had not Guicciardini exhorted him to remain. He drew up a defence for him, and by a judicious distribution of bribes, succeeded in obtaining his acquittal; and Florence was again subjected to his yoke.

Two years after, Alexander was murdered by Lorenzino de' Medici, who considered that he had a better right to be considered the head of the family. But this act, undertaken without the participation of any accomplice, was not followed by the results that might have been anticipated. Lorenzino, frightened by his very success, fled the city, and his cousin Cosmo was raised to the supreme power, and afterwards named grand duke of Tuscany. Guicciardini assisted materially in his elevation, and hoped to be real chief of the state, while the other held the nominal rank. But Cosmo was of a crafty, cold, and ungrateful disposition, and treated his benefactor with such neglect, that he withdrew himself from public life, and retired to his country seat at Montici, in the neighbourhood of Florence.

From this time he occupied himself wholly in the composition of his history. It is a fine monument of his genius and industry. It commences with the invasion of Italy by Charles VIII., and goes down to the exaltation of Cosmo. The fault attributed to him as an author is prolixity, and to this he must plead guilty. He dwells with the most tiresome and earnest minuteness on the most trivial incidents; and the taking of an insignificant castle, followed by no important results, is attended by the same diffuseness and exactitude of detail as events of the greatest magnitude. But no historian surpasses Guicciardini when the subject is worthy of his pen. His animated descriptions of battles, the chances of war, and conduct of princes and leaders; his delineations of character, and masterly views of the course of events, all claim the highest admiration. The orations, which he intersperses, have been cavilled at, but they are eloquent, full of dignified exhortation, or sagacious reasoning. His account of the rise and formation of the temporal power of the popes excited great censure in catholic countries; and throughout he is accused of showing himself the enemy of the Roman church. It is true, that the pages of no other historian afford such convincing proofs of the pernicious effects resulting from the union of spiritual supremacy and temporal possessions. His powerful character of the infamous pope Borgia; his description of the fiery vehemence of Julius II.; his unveiling of the faults of Leo X., and the exposure he makes of the mistakes and weakness of Clement VII., present the very men and times to our eyes, and form as it were a school in which to study the philosophy of history. We perceive no partiality till the last few pages, which record the downfall of the republic of Florence. His language is, in the eyes of Italian critics, nearly pure; it is forcible, without being concise; and the clearness and majesty of the expressions in his best passages carry the reader along with him.

Guicciardini was solicited by pope Paul III. to leave his retreat, and to enter again on public life, but he refused. The disappointment of his ambitious views on the exaltation of Cosmo, and the duke's ingratitude, struck him to the heart. He did not live to complete his history, and died on the 27th of May, 1540, in the fifty-eighth year of his age. He expressly ordered that his funeral should be unattended by any pomp; and his directions were so strictly followed, that for some time no stone even commemorated the spot of his sepulture.

Little is known of his private life. His letters have all perished, except a few addressed to Machiavelli. They are lively in their style, and very friendly. He had no son, and seven daughters, and wrote to the secretary to ask his advice in settling them in marriage. Machiavelli advised his applying to the pope for a dowry; counselling him by all means to marry the eldest well, as the others would follow her example; and he quotes a passage from Dante, referring to a duke of Provence, "who had three daughters and each a queen. And the cause of this thing, was Romeo, a poor wandering man," who had advised the duke to be unsparing in his dowry to his eldest daughter, so to command a splendid alliance, as the best means to advance her sisters also. He gave her half his duchy, and she married the king of France. Guicciardini in reply says, "You have set me on ransacking Romagna for a copy of Dante, and at last I have found one." But he was too high-spirited to apply for a gift from the pope.