His flaggy wings when forth he did display,
  Were like two sails, in which the hollow wind
  Is gathered full, and worketh speedy way:
  And eke the pennes, that did his pinons bind,
  Were like main-yards, with flying canvas lind,
  With which whenas him list the air to beat,
  And there by force unwanted passage find,
  The clouds before him fled for terror great,
And all the heavens stood still amazed with his threat.

Book I, Canto XI