Petrarch returned next day for Parma.  We find, from the original fragments of his poems, brought to light by Ubaldini, that he was occupied in retouching them during the summer which he passed at Parma, waiting for the termination of the excessive heats, to go to Rome and attend the jubilee.  With a view to make the journey pleasanter, he invited Guglielmo di Pastrengo to accompany him, in a letter written in Latin verse.  Nothing would have delighted Guglielmo more than a journey to Rome with Petrarch; but he was settled at Verona, and could not absent himself from his family.

In lieu of Pastrengo, Petrarch found a respectable old abbot, and several others who were capable of being agreeable, and from their experience, useful companions to him on the road.  In the middle of October, 1350, they departed from Florence for Rome, to attend the jubilee.  On his way between Bolsena and Viterbo, he met with an accident which threatened dangerous consequences, and which he relates in a letter to Boccaccio.

“On the 15th of October,” he says, “we left Bolsena, a little town scarcely known at present; but interesting from having been anciently one of the principal places in Etruria.  Occupied with the hopes of seeing Rome in five days, I reflected on the changes in our modes of thinking which are made by the course of years.  Fourteen years ago I repaired to the great city from sheer curiosity to see its wonders.  The second time I came was to receive the laurel.  My third and fourth journey had no object but to render services to my persecuted friends.  My present visit ought to be more happy, since its only object is my eternal salvation.”  It appears, however, that the horses of the travellers had no such devotional feelings; “for,” he continues, “whilst my mind was full of these thoughts, the horse of the old abbot, which was walking upon my left, kicking at my horse, struck me upon the leg, just below the knee.  The blow was so violent that it sounded as if a bone was broken.  My attendants came up.  I felt an acute pain, which made me, at first, desirous of stopping; but, fearing the dangerousness of the place, I made a virtue of necessity, and went on to Viterbo, where we arrived very late on the 16th of October.  Three days afterwards they dragged me to Rome with much trouble.  As soon as I arrived at Rome, I called for doctors, who found the bone laid bare.  It was not, however, thought to be broken; though the shoe of the horse had left its impression.”

However impatient Petrarch might be to look once more on the beauties of Rome, and to join in the jubilee, he was obliged to keep his bed for many days.

The concourse of pilgrims to this jubilee was immense.  One can scarcely credit the common account that there were about a million pilgrims at one time assembled in the great city.  “We do not perceive,” says Petrarch, “that the plague has depopulated the world.”  And, indeed, if this computation of the congregated pilgrims approaches the truth, we cannot but suspect that the alleged depopulation of Europe, already mentioned, must have been exaggerated.  “The crowds,” he continues, “diminished a little during summer and the gathering-in of the harvest; but recommenced towards the end of the year.  The great nobles and ladies from beyond the Alps came the last.”