Though the motte to the south-west of the present castle is now called "Ethelfleda's Mound" ('Ethelfleda' being an alternative form of Æthelflæd), it is in fact part of the later Norman fortifications, and not of Anglo-Saxon origin.
Selv om motten i den sydvestlige del af den nuværende borg bliver kaldt "Ethelfleda's Mound" er det i virkeligheden en del af en senere normannisk befæstning og ikke af angelsaksisk oprindelse.