Bob and wheel in the context of "Cadenza"

Sir Gawain and the Green Knight is a late 14th-century chivalric romance in Middle English alliterative verse. The author is unknown; the title was given centuries later. It is one of the best-known Arthurian stories, with its plot combining two types of folk motifs: the beheading game and the exchange of winnings. Written in stanzas of alliterative verse, each of which ends in a rhyming bob and wheel, it draws on Welsh, Irish, and English stories, as well as the French chivalric tradition. It is an important example of a chivalric romance, which typically involves a hero who goes on a quest that tests his prowess. It remains popular in modern English renderings from J. R. R. Tolkien, Simon Armitage, and others, as well as through film and stage adaptations.

The story describes how Sir Gawain, who was not yet a knight of King Arthur's Round Table, accepts a challenge from a mysterious "Green Knight" who dares any man to strike him with his axe if he will take a return blow in a year and a day. Gawain accepts and beheads him, after which the Green Knight stands, picks up his head, and reminds Gawain of the appointed time. In his struggles to keep his bargain, Gawain demonstrates chivalry and loyalty until his honour is called into question by a test involving the lord and the lady of the castle at which he is a guest. The poem survives in one manuscript, Cotton Nero A.x., which also includes three religious narrative poems: Pearl, Cleanness, and Patience. All four are written in a North West Midlands dialect of Middle English, and are thought to be by the same author, dubbed the "Pearl Poet" or "Gawain Poet".