 There are doubts , however , whether the swords known to have been at Żółkiew in 1738 and at Nieśwież two years later , were in fact the same sword . The <unk> ' castle was plundered by the Russian army in 1812 and the subsequent fate of their replica of Szczerbiec is unknown . This fact cast doubts over the authenticity of Szczerbiec held in the Hermitage . Some experts suspected that the sword possessed by the Russian imperial museum was in fact the Nieśwież replica , not part of the original royal insignia . 
