During his half-retirement, Petrarch learned news which disturbed his repose. A courier arrived, one night, bringing an account of the entire destruction of the Genoese fleet, in a naval combat with that of the Venetians, which took place on the 19th of August, 1353, near the island of Sardinia. The letters which the poet had written, in order to conciliate those two republics, had proved as useless as the pacificatory efforts of Clement VI. and his successor, Innocent. Petrarch, who had constantly predicted the eventual success of Genoa, could hardly believe his senses, when he heard of the Genoese being defeated at sea. He wrote a letter of lamentation and astonishment on the subject to his friend Guido Settimo. He saw, as it were, one of the eyes of his country destroying the other. The courier, who brought these tidings to Milan, gave a distressing account of the state of Genoa. There was not a family which had not lost one of its members.

Petrarch passed a whole night in composing a letter to the Genoese, in which he exhorted them, after the example of the Romans, never to despair of the republic. His lecture never reached them. On awakening in the morning, Petrarch learned that the Genoese had lost every spark of their courage, and that the day before they had subscribed the most humiliating concessions in despair.

It has been alleged by some of his biographers that Petrarch suppressed his letter to the Genoese from his fear of the Visconti family. John Visconti had views on Genoa, which was a port so conveniently situated that he naturally coveted the possession of it. He invested it on all sides by land, whilst its other enemies blockaded it by sea; so that the city was reduced to famine. The partizans of John Visconti insinuated to the Genoese that they had no other remedy than to place themselves under the protection of the Prince of Milan. Petrarch was not ignorant of the Visconti's views; and it has been, therefore, suspected that he kept back his exhortatory epistle from his apprehension, that if he had despatched it, John Visconti would have made it the last epistle of his life. The morning after writing it, he found that Genoa had signed a treaty of almost abject submission; after which his exhortation would have been only an insult to the vanquished.

The Genoese were not long in deliberating on the measures which they were to take. In a few days their deputies arrived at Milan, imploring the aid and protection of John Visconti, as well as offering him the republic of Genoa and all that belonged to it. After some conferences, the articles of the treaty were signed; and the Lord of Milan accepted with pleasure the possession that was offered to him.

Petrarch, as a counsellor of Milan, attended these conferences, and condoled with the deputies from Genoa; though we cannot suppose that he approved, in his heart, of the desperate submission of the Genoese in thus throwing themselves into the arms of the tyrant of Italy, who had been so long anxious either to invade them in open quarrel, or to enter their States upon a more amicable pretext. John Visconti immediately took possession of the city of Genoa; and, after having deposed the doge and senate, took into his own hands the reins of government.

Weary of Milan, Petrarch betook himself to the country, and made a temporary residence at the castle of St. Columba, which was now a monastery. This mansion was built in 1164, by the celebrated Frederick Barbarossa. It now belonged to the Carthusian monks of Pavia. Petrarch has given a beautiful description of this edifice, and of the magnificent view which it commands.

Whilst he was enjoying this glorious scenery, he received a letter from Socrates, informing him that he had gone to Vaucluse in company with Guido Settimo, whose intention to accompany Petrarch in his journey to Italy had been prevented by a fit of illness. Petrarch, when he heard of this visit, wrote to express his happiness at their thus honouring his habitation, at the same time lamenting that he was not one of their party. "Repair," he said, "often to the same retreat. Make use of my books, which deplore the absence of their owner, and the death of their keeper" (he alluded to his old servant). "My country-house is the temple of peace, and the home of repose."

From the contents of his letter, on this occasion, it is obvious that he had not yet found any spot in Italy where he could determine on fixing himself permanently; otherwise he would not have left his books behind him.

When he wrote about his books, he was little aware of the danger that was impending over them. On Christmas day a troop of robbers, who had for some time infested the neighbourhood of Vaucluse, set fire to the poet's house, after having taken away everything that they could carry off. An ancient vault stopped the conflagration, and saved the mansion from being entirely consumed by the flames. Luckily, the person to whose care he had left his house—the son of the worthy rustic, lately deceased—having a presentiment of the robbery, had conveyed to the castle a great many books which Petrarch left behind him; and the robbers, believing that there were persons in the castle to defend it, had not the courage to make an attack.

As Petrarch grew old, we do not find him improve in consistency. In his letter, dated the 21st of October, 1353, it is evident that he had a return of his hankering after Vaucluse. He accordingly wrote to his friends, requesting that they would procure him an establishment in the Comtat. Socrates, upon this, immediately communicated with the Bishop of Cavaillon, who did all that he could to obtain for the poet the object of his wish. It appears that the Bishop endeavoured to get for him a good benefice in his own diocese. The thing was never accomplished. Without doubt, the enemies, whom he had excited by writing freely about the Church, and who were very numerous at Avignon, frustrated his wishes.