Columbia subject headings:
Grail--Legends.
Harvard subject headings:
Grail--Legends
Perceval (Legendary character)--Romances.
Princeton subject headings:
Arthurian romances.
Grail--Romances.
Knights and knighthood--Romances.
Perceval (Legendary character)--Romances.
Romances, German--Translations into English.
Romances.