Columbia subject headings:
English literature--Middle English, 1100-1500--History and criticism.
Grail.
Longinus, Saint, martyr, active 1st century.
Harvard subject headings:
English literature--Middle English, 1100-1500--History and criticism
Grail--Legends--History and criticism
Holy Lance--Legends--History and criticism.
Longinus, Saint, martyr, active 1st century--Legends--History and criticism.
Princeton subject headings:
English literature--Middle English, 1100-1500--History and criticism.
Grail.
Longinus, Saint, martyr, active 1st century.