This article focuses on the centrality provided to auctores and texts as corpora, in the framework of Francesco Petrarch and the theory of imitation by the humanists. Initially, animal images from Petrarch and the humanists are analysed, as well as the paths of their diffusion. These were used to express the role of the model, the involvement of the writer, variatio, the election of stilus, and the questions sustained by Ciceronianism. Then, tree main methodological ways to study the relationship between texts as corpora are presented: semiosphere, intertextuality, and reception theory. A critic view point regards static methodologies. Conclusively, the dialogue between Petrarch and Cicero, as text and corpus, is recalled in order to incorporate the auctores contamination.