Which medieval poem inspired Tolkien’s 1925 scholarly edition with E.V. Gordon?

Sir Gawain and the Green Knight inspired Tolkien’s 1925 scholarly edition with E.V. Gordon. Their edition, titled Sir Gawain and the Green Knight, remains an important work in the study of the Middle English poem.

The poem tells of Sir Gawain, a knight of King Arthur’s court, who accepts a supernatural challenge from the Green Knight. Its themes include courage, courtesy, temptation, honor, and the limits of human virtue.

Tolkien’s expertise in medieval languages and literature shaped both his academic career and his fiction. His translation and criticism of medieval texts helped establish his reputation before The Hobbit and The Lord of the Rings made him internationally famous.

The poem is sometimes confused with Beowulf because Tolkien was also a major Beowulf scholar and delivered the influential lecture “Beowulf: The Monsters and the Critics” in 1936. Pearl is another Middle English poem associated with the same manuscript tradition, but it is not the answer here.