• A page from the Archimedes Palimpsest, considered lost for several decades, has been identified by a CNRS researcher at the Musée des Beaux-Arts in Blois.• The leaf contains a passage from the treatise On the Sphere and the Cylinder on one side, which remains legible, while the other side is obscured by an illumination added in the twentieth century.• This discovery paves the way for further analyses aimed at improving the reading of the ancient text. A page long believed to have been lost from the Archimedes Palimpsest, one of the most important surviving manuscripts of antiquity, has been identified at the Musée des Beaux-Arts in Blois, central France, by a CNRS researcher. Initial analysis confirms that the page corresponds to page 123 of the Palimpsest and contains a passage from Archimedes’ treatise « On the Sphere and the Cylinder », Book I, Propositions 39 to 41. The discovery is presented in an article published on 6 March 2026 in Zeitschrift für Papyrologie und Epigraphik.