The collection of the atelier du moulage at the Royal Museums for Art and History, Brussels contains interesting examples of fictile ivory casts of Byzantine, early Christian and Gothic ivories. The collections, deliberately heterogeneous in conception, hold some 36 casts and moulds of Gothic ivory carvings. Their collecting pattern followed - it would initially seem - no particular plan. This article asks whether this is in fact the case. Through an analysis of the history of the atelier de moulage it becomes clear that a strong link between the Belgian government and the museum was responsible for the development of the collection of moulds and plaster casts.