Columbia subject headings:
Grail--Legends.
Low German language--To 1500--Texts.
Merlin (Legendary character)
Harvard subject headings:
Grail--Legends
Low German language--To 1500--Texts.
Merlin (Legendary character)--Legends.
Princeton subject headings:
Grail--Legends.
Legends.
Merlin (Legendary character)--Legends.