Morris Bishop, Petrarch and His World (Chp. 22):
He [Petrarch] was one of the world’s great letter-writers. “I can’t stop writing letters unless I stop living,” he said. He put a high value on his messages. When one was ready, a secretary was put to copying it, and woe to him if he erred or blotted! He could not bear to have his missives disregarded. He wrote to Laelius: “You’ve been idle about answering my letters. Well, dukes and monarchs answer them.” A letter was mislaid; the whole house was in a turmoil for a day while everyone hunted it in vain. “It was sweet to write, sweeter to read over, and very bitter to remember.”
The contents are extremely varied, in both substance and in style. Some are cheery anecdotes of daily life, comic incidents, news of his doings, his friends, his garden, his reading. Some are reflections on current events, and some political exhortations to Emperors and Popes. Many are moral essays, satires, portraits, having little to do with the concerns of his correspondent. Indeed, they may have been written with no correspondent in mind, and have been sent off when a messenger turned up on his way to some city where a friend dwelt. Most of them are deliberately literary in character and style. The writer was looking beyond the immediate addressee to the ultimate recipient, posterity.
For the modern reader, temporary posterity, his work has many faults. He is often intolerably garrulous, repetitive, sententious, obtuse. Some of his letters of consolation, recommending stoic insensibility, must have caused angry tears to flow. He even tells Philippe de Cabassoles that the death of his brother should be rather an occasion for rejoicing than grief. He stuffs his letters with quotations from the Roman classics, which fortunately are easy to skip. But of course such quotations were more honored and less accessible then than now.
[Morris Bishop, Petrarch and His World (Indiana University Press, 1963) p. 280]