Excavations carried out in 2012 in the town of Brissay-Choigny (Picardy), in a place called "La Prélette", on the site of a palaeochannel of the Oise River, revealed a medieval winged spear with a sheath, a remarkable and unprecedented discovery in France. The anaerobic nature of the environment has enabled part of the shaft to be preserved, as welle as the wooden sheath and its chape. Although the spear could not be associated with a stratigraphic context, it was dated by typo-chronology between the 9th and the 12th century. The aim here is to provide some elements of analysis and reflection on an exceptional object, unprecedented for France and most certainly also for Europe.