Morel
In Chrétien's Cliges, Morel is the black charger Cligés rode on the first day of the Oxford tournament.
Strangely, Morel is the only one of the four - black, sorrel, tawny, and white - to whom Chrétien de Troyes seems to give a name. Yet, of the four, the white Arabian, won from the Duke of Saxony, was surely the finest and most valuable. Perhaps in Morel's case D.D.R. Owen has simply translated a name for the color as a proper noun?
In Durmart le Gallois, Sir Sagremor owns a horse of the same name.