Ephemeral creatures, celestial spaces, universes furrowed by distant chimeras fill the works of the two artists compared in this thesis. Luigi Ontani, with his oriental colors and his flair, has a nonindifferent charm. His being outside the box makes him unique and without any prejudice. He is the living manifesto of freedom of expression. Likewise, the works of Hieronymus Bosch have an esoteric and magical flavor: the Garden of Earthly Delights or the Marriage Feast at Cana are real triumphant works of visionary and fantastic art.