The main aim of the dissertation is to describe duality, a characteristic inextricably linked with Centaurs, Fauns, Dionysus, Bacchantes, Glaucus and other second-rate Greco- Roman gods in the poetry of ten 19th century French writers. Having explained the symbolism of these dual and hybrid mythological creatures in antique frames, we focused on literary processing and interpretation they inspired in 19th century French literature which resulted in new findings on the duality that does not remain exclusively tied to poets and heroes of their poems, but as an every-man's feature, torn by self-contradictions and dilemmas, presents a picture of general human dualism. Eventually, the analysis showed that some Parnassian poets like Théodore de Banville, Charles-Marie Leconte de Lisle, José-Maria de Heredia as well as their spiritual father from the very end of 18th century André Chénier thematized these ancient deities more or less for aestetic reasons, while the inspiration for these characters in the poetry of Romanticism (Maurice de Guérin, Victor Hugo), the Decadent Movement (Jules Laforgue) and Symbolism (Henri de Régnier, Arthur Rimbaud, Paul Verlaine, Stéphane Mallarmé) comes from dual nature of these writers.