Although transparent because of its physical features, and despite it is one of the most sumptuous Carolingian intaglios still preserved, the rock crystal depicting the Baptism of Christ did not enjoy a clear history before its acquisition by the Rouen Musée des Antiquités. This article suggests to explore a Reims provenance and to dismiss its attribution to Lotharingia. A reconsideration of the available archives and textual material, a fresh understanding of its iconography in the light of the prestige propaganda developed by Hincmar for his archiepiscopal seat of Reims, but also a new approach for its stylistical analysis, invite us to consider the Rouen Baptism as a membrum disjectum from St. Remigius's shrine, erected by Hincmar in 852. Its narrow affiliation with the Lothair Crystal incites us to give this last intaglio to the Reims artistic milieu and to rule out the attribution of the two crystals to the so-called "Later Metz School".