Sir Gawain and the Green Knight is a late 14th-century Middle English alliterative romance outlining an adventure of Sir Gawain, a knight of King Arthur's Round Table. In the tale, Sir Gawain accepts a challenge from a mysterious warrior who is completely green, from his clothes and hair to his beard and skin. The "Green Knight" offers to allow anyone to strike him with his axe if the challenger will take a return blow in a year and a day. Gawain accepts, and beheads him in one blow, only to have the Green Knight stand up, pick up his head, and remind Gawain to meet him at the appointed time. The story of Gawain's struggle to meet the appointment and his adventures along the way demonstrate the spirit of chivalry and loyalty.

The poem survives in a single manuscript, the Cotton Nero A.x., that also includes three religious pieces, Pearl, Cleanness, and Patience. These works are thought to have been written by the same unknown author, dubbed the "Pearl Poet" or "Gawain Poet." All four narrative poems are written in a North West Midland dialect of Middle English.[1][2] The story thus emerges from the Welsh and English traditions of the dialect area, borrowing from earlier "beheading game" stories and highlighting the importance of honour and chivalry in the face of danger.

In addition to its complex plot and rich language, the poem's chief interest for literary critics is its sophisticated use of medieval symbolism. Everything from the Green Knight, to the beheading game, to the girdle given to Gawain as protection from the axe, is richly symbolic and steeped in Celtic, Germanic, and other folklore and cultural traditions. The Green Knight, for example, is interpreted by some as a representation of the Green Man of Celtic legend and by others as an allusion to Christ.

Sir Gawain and the Green Knight is an important poem in the romance genre, which typically involves a hero who goes on a quest that tests his ability. The ambiguity of the poem's ending, however, makes it more complex than most. Christian readings of the poem argue for an apocalyptic interpretation, drawing parallels between Gawain and Lady Bertilak and the story of Adam and Eve. Feminist interpretations disagree at the most basic level, some arguing that women are in total control from beginning to end, while others argue that their control is only an illusion. Cultural critics have argued that the poem is best read as an expression of tensions between the Welsh and English present at the time in the poet's dialect region. The poem remains popular to this day, through translations from renowned authors like J. R. R. Tolkien and Simon Armitage, as well as through recent film and stage adaptations.