Which medieval poem did J.R.R. Tolkien and E.V. Gordon publish an influential edition of in 1925?

J.R.R. Tolkien and E.V. Gordon published an influential edition of Sir Gawain and the Green Knight in 1925.

Their edition helped establish the poem as a major work of Middle English literature and remains important in the history of Tolkien’s academic career. Tolkien later translated the poem, and his translation was published posthumously in 1975 together with Pearl and Sir Orfeo.

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

Tolkien’s scholarship on medieval texts influenced his creative writing, though Sir Gawain and the Green Knight is not a Middle-earth story. Readers sometimes connect it directly to fantasy novels because of its supernatural imagery, but it is a late-fourteenth-century English poem.