To grasp how a discussion of the myth of Hercules could have developed into a sweeping encyclopaedic work, we must first recall the importance of Seneca in the culture of the 14th century. De laboribus Herculis clearly reflects Salutati’s attentive analysis of Seneca’s two Hercules tragedies, particularly Hercules furens. There are two versions of De laboribus Herculis (both unfinished), which Salutati must have commenced after 1375. The work’s initial intent was to offer an interpretation of the two tragedies, highlighting the different characteristics of Hercules in each one. This interpretative work was to be accomplished through the use of allegory. However, Salutati’s goal gradually shifted to a thorough and almost encyclopaedic treatment of the myth of Hercules, albeit maintaining an allegorical and thus moral interpretation of ancient poetry.

De laboribus Herculis emerges as the quintessential ‘receptacle’ of Salutati’s literary and scholarly knowledge. In it he cites Seneca, Virgil, Ovid, the Third Vatican Mythographer, Fulgentius, Catullus, Hyginus, Pomponius Mela, Vibius Sequester, Plautus; there are substantial references to medieval culture, with Bernard Sylvester, Eberard of Béthune, the Graecismus, Peter Comestor, the Physiologus, Solinus, Rabanus Maurus, Martianus Capella, Vincent of Beauvais, Vitalis of Blois, the Latin Aristotle, and the great encyclopaedic, lexical and etymological collections. Biblical references also abound. An examination of the variety of sources alone, essentially divided equally between the classics and medieval works, reveals the inherent contradiction in De laboribus Herculis: although conceived and structured according to the models typical of the preceding era, it reflects a powerfully innovative humanistic spirit in its reference to classical writers (some of whom recently rediscovered) whose works Salutati had read first-hand.