The article concerns the dating of a medallion from the collections of the Kórnik Library. The medallion is interesting both in view of its author (David d’Argers was one of the most eminent French sculptors), and the person portrayed by it (Klaudyna Potocka née Działyńska was among the most famous Polish women of the Romanticism). Castings of the medallion are kept in several Polish museums. In all of their catalogues, the castings are dated to 1831. However, both the biographic data and Potocka’s correspondence clearly indicate that they should be dated to 1834, which is the focus of what I have attempted to demonstrate.