#150 En Las Dos Torres:
For Gandalf took the horse that is called Shadowfax, the most precious of all the king's steeds, chief of the Mearas, which only the Lord of the Mark may ride.
'Nor will you again,' said Gandalf. 'That is Shadowfax. He is the chief of the Mearas, lords of horses, and not even Thjoden, King of Rohan, has ever looked on a better.
Never have we seen other riders so strange, nor any horse more proud than is one of these that bear you. He is One of the Mearas, unless our eyes are cheated by some spell. Say, are you not a wizard, some spy from Saruman, or phantoms of his craft? Speak now and be swift!'