At Avignon, where he appeared in August 1352, Rienzi was tried by three cardinals, and was sentenced to death, but this judgment was not carried out, and he remained in prison in spite of appeals from Petrarch for his release.
But, flattering as was the offer, Petrarch declined it.
Their historical importance, their spiritual fragrance and their literary value combine to put their author almost on a level with Petrarch as a 14th century letter-writer.
From Petrarch to the Epistolae obscurorum virorum there is a whole epistolary literature.
The language of Tuscany is remarkable for its purity of idiom, and its adoption by Dante and Petrarch probably led to its becoming the literary language of Italy.
The Divine Comedy, the Canzoniere and the Decameron were works of monumental art, deriving neither form nor inspiration immediately from the classic's, but applying the originality of Italian genius Petrarch to matter drawn from previous medieval sources.
Had Petrarch been possessed with a passion for some commanding principle in politics, morality or science, instead of with the thirst for selfglorification and the ideal of artistic culture, it is not wholly impossible that Italian humanism might have assumed a manlier and more conscientious tone.
It was the opinion of Petrarch that, had Urban remained in Rome, he would have been entitled to rank with the most distinguished men of his era; and, if we discount this single act of weakness, he must be classed as one of the noblest and best of popes.
Petrarch was not only the imitator of Virgil, who had been the leading name in Latin letters throughout the middle ages; it was the influence of Petrarch that gave a new prominence to Cicero.
So much had to be premised in order to make it clear in what relation humanism stood to the Renaissance, since the Italian work of Dante, Petrarch and Boccaccio is sufficient to indicate the re-birth of the spirit after ages of apparent deadness.