The aim of this paper is to analyse the process of writing Les roques i el mar, el blau by the Catalan poet Salvador Espriu. At the origin of the final work there was a collection of 52 texts written in 1976 to comment and to present 52 drawings about figures from the Greek and Latin tradition by the artist Cèsar Estrany. In these texts Espriu expresses ironically his dislike for the kind of representation by Estrany as well as for some mythical figures and stories. He also rewrites some myths (about Ganimedes, Danae, Orpheus) as an exercise of transgression, which is the seed for the series of the other 48 that complete the whole book in 1981. So became the former collection of texts a powerful mythological summa in which the author criticizes some received ideas on classical tradition and exposes his pessimistic vision of the world.