The knight gan fairly couch his steady spear,
  And fiercely ran at him with rigorous might:
  The pointed steel arriving rudely there,
  His harder hide would neither pierce, nor bite,
  But glancing by forth passed forward right;
  Yet sore amoved with so puissant push,
  The wrathful beast about him turned light,
  And him so rudely passing by, did brush
With his long tail, that horse and man to ground did rush.

Both horse and man up lightly rose again,
  And fresh encounter towards him addressed:
  But th'idle stroke yet back recoiled in vain,
  And found no place his deadly point to rest.
  Exceeding rage enflam'd the furious beast,
  To be avenged of so great despite;
  For never felt his impierceable breast
  So wondrous force, from hand of living wight;
Yet had he prou'd the power of many a puissant knight.

Book I, Canto XI