He wrote to Boccaccio on the subject.

He repeats the belief, at that time generally entertained, that the sixty-third year of a man's life is its most dangerous crisis.

It was a belief connected with astrology, and a superstitious idea of the influence of numbers; of course, if it retains any attention at present, it must subsist on practical observation: and I have heard sensible physicians, who had no faith in the influence of the stars, confess that they thought that time of life, commonly called the grand climacteric, a critical period for the human constitution.
In May, 1367, Pope Urban accomplished his determination to remove his court from Avignon in spite of the obstinacy of his Cardinals; but he did not arrive at Rome till the month of October.

He was joyously received by the Romans; and, in addition to other compliments, had a long letter from Petrarch, who was then at Venice.

Some days after the date of this letter, our poet received one from Galeazzo Visconti.