IRONSIDES, a nickname given to one of great bravery, strength or endurance, particularly as exhibited in a soldier. In English history Ironside or Ironsides first appears as the name of Edmund II., king of the English. In the Great Rebellion it was first given by Prince Rupert to Cromwell, of ter the battle of Marston Moor in 1644. From Cromwell it was transferred to the troopers of his cavalry, those "god-fearing men," raised and trained by him in an iron discipline.