Though when he saw no power might prevail,
  His trusty sword he called to his last aid,
  Wherewith he fiercely did his foe assail,
  And double blows about him stoutly laid,
  That glancing fire out of the iron plaid;
  As sparkles from the Anvil use to fly,
  When heavy hammers on the wedge are swayed;
  Therewith at last he forced him to untie
One of his grasping feet, him to defend thereby

The other foot, fast fixed on his shield,
When as no strength, nor strokes might him constrain
To loose, nor yet the warlike pledge to yield,
He smote thereat with all his might and main,
That nought so wondrous puissance might sustain;
Upon the joint the lucky steel did light,
And made such way, that hewed it quite in twain;

Book 1, Canto 11