De viris illustribus (English: On Illustrious Men) is an unfinished collection of biographies, written in Latin, by the 14th-century Italian author Francesco Petrarca. These biographies are a set of Lives similar in idea to Plutarch's Parallel Lives. The works were unfinished. However he was famous enough for these and other works to receive two invitations to be crowned poet laureate. He received these invitations on exactly the same day, April 8, 1341, one being from the Paris University and the other from the Roman Senate. He accepted the Roman invitation. It is composed of two books: Liber I includes 24 to 36 moral biographies (depending on version) of heroes of Greek and Roman antiquity (much like Polybius The Histories and Plutarch's figures in his Lives). Liber II includes 12 moral biographies of Biblical and mythical figures (much like that found in the Hebrew Bible and Greek mythology). There is an English translation of the prefaces to De viris illustribus.