De viris illustribus
It seems like Petrarch had the idea to write up a list of biographies of Roman leaders ("Illustrious Men") from the republican period before that of the "Africa". Petrarch was preoccupied with this idea of a series of biographies of Lives of ancient heroes ("De viris illustribus") of generals and statesmen for almost forty years until his death and can be viewed as part of his total intellectual development. There were several plans of "De viris illustribus". In 1348-49 Petrarch made a larger version of Lives in his work on these "Famous Men." Petrarch then went from these Lives of "Illustrious Men" into his work on the "Africa" using the research of "De viris illustribus" as the bases. Petrarch writes a letter to Luca Cristiani in 1349 concerning these Lives for "De viris illustribus" and his epic poem "Africa" that he was doing in the valley at Vaucluse;