De casibus virorum illustrium (On the Fates of Famous Men) is a work of 56 biographies in Latin prose composed by the Florentine poet Giovanni Boccaccio of Certaldo in the form of moral stories of the falls of famous people, similar to his work of 106 biographies De Mulieribus Claris.

The forceful written periodic Latin work was far more widely read then the now famous vernacular Tuscan/Italian tales of Decameron.

[9] The Renaissance period saw the secular biography development which was spearheaded partly by the success of this work being a stimulus and driving force of the new biography-moral genre.

[11] Boccaccio relates biographies of famous people who were at the height of happiness and fell to misfortune when they least expected it.

[13] Only the historical figures whose names feature in chapter titles (i.e., whose lives are recounted more at lenght) are reported; the total number is far greater.