Which poem did J.R.R. Tolkien edit with E. V. Gordon in a 1925 scholarly edition?

J.R.R. Tolkien edited Sir Gawain and the Green Knight with E. V. Gordon in a 1925 scholarly edition.

The Middle English poem tells of Sir Gawain, a knight of King Arthur’s court, who accepts a mysterious challenge from the Green Knight. Tolkien and Gordon’s edition helped establish the poem as a major subject of modern medieval scholarship.

Tolkien’s work on the poem reflected his expertise in Middle English language and literature. He later translated Sir Gawain and the Green Knight into modern English prose, with the translation published after his death in 1975.

Beowulf was another major focus of Tolkien’s scholarship, but it was not the poem named in the 1925 edition with Gordon. The two works are often linked because both are central to Tolkien’s academic reputation.