And over, all with brazen scales was armed,
  Like plated coat of steel, so couched near,
  That nought mote pierce, nay might his corpse be harmed
  With dint of sword, nor push of pointed spear;
  Which as an Eagle, seeing prey appear,
  His airy plumes doth rouse, full rudely dight,
  So shaked he, that horror was to hear,
  For as the clashing of an Armour bright,
Such noise his roused scales did send unto the knight.

Book I, Canto XI