'Suddenly the King cried to Snowmane and the horse sprang away. Behind him his banner blew in the wind, white horse upon a field of green, but he outpaced it. After him thundered the knights of his house, but he was ever before them. Éomer was there, the white horsetail on his helm floating in his speed, and the front of the first éored roared like a breaker foaming to the shore, but Théoden could not be overtaken. Fey he seemed, or the battle-fury of his fathers ran like new fire in his veins, and he was borne up on Snowmane like a god of old, even as Oromë the Great in the battle of the Valar when the world was young.'
JRR Tolkien: The Lord of the Rings: The Return of the King: Book V, Chapter 5: The Ride of the Rohirrim