In this Comparative Literature analysis, the legacy of Greek antiquity in the works of the Italian Romantic poet Giacomo Leopardi (1798-1837) is studied in its European context, with references to such authors as Schiller, Hoelderlin, and Shelley. The monograph is structured in three main chapters, focused on Sappho, Classical Mythology, and Platonism respectively. An extensive Introduction and Conclusion expand the scope of the study to a philosophical reflection on Pessimism along the lines of Schopenhauer's and Nietzsche's thought.