Wikipedia
Gornemant
Gornemant was Percival's mentor in Arthurian legend. As he does not know how to behave like a knight, Gornemant advises him not to ask too many questions.
He is mentioned in a few early romances, but achieves prominence in Chrétien de Troyes' Perceval, the Story of the Grail, where he instructs the young hero in the ways of knighthood.
Gornemant's niece is Blanchefleur, whom Percival later marries after successfully defending her city against attackers.
This character became famous as Gurnemanz in Richard Wagner's opera Parsifal, in which he is one of the main Grail Knights.