Extremely little is known about the origins of Sir Gawain and the Green Knight. The poem survived the Middle Ages in a single manuscript that was preserved because it fell into the hands of a book collector, Sir Robert Cotton, whose collections were later donated to the British Museum. There, the poem was rediscovered by scholars during the early nineteenth century, and it has been recognized as a masterpiece of English literature ever since. The fact that the Sir Gawain and the Green Knight appears in only one manuscript should not be taken as evidence that it fell into immediate obscurity after it was written. In fact, many works of medieval literature have been lost to history or exist in only a handful of copies. Sir Gawain and the Green Knight was popular enough to have spawned a bad imitation, usually called The Greene Knight to distinguish it from the original.
The manuscript in which Sir Gawain and the Green Knight appears, known as Cotton Nero A.x., contains three other poems. On the basis of their similarities in style, language, and theme, all four are believed to be by the same poet. None of the poems has a title in the manuscript, but the three are usually called Pearl, Patience, and Cleanness (or Purity). Those three poems have more obviously religious themes than Sir Gawain and the Green Knight: Patience retells of the story of Jonah and the whale; Pearl offers a dream-vision of heaven; and Cleanness uses three episodes from the Bible (the Flood, Sodom and Gomorrah, and Balshazzar's Feast) to illustrate the ideal of purity. Some scholars believe that a fifth poem, Saint Erkenwald, found in a different manuscript, is also by the same poet. The Cotton Nero manuscript was most likely produced by a copyist, not the poet, and there is no way to determine how many copies away from the original it is. The manuscript itself dates around 1400, and scholars have dated the composition of the poems anywhere from about 1350 to 1400.
The poet was a contemporary of the famous Geoffrey Chaucer, who wrote the Canterbury Tales, and both poets wrote in an older form of English known as Middle English. During this period, numerous English regional dialects existed. Chaucer was writing his poems in the dialect of London, which became the ancestor of modern English, so most modern readers can puzzle out Chaucer's language with a little assistance. However, the English of Sir Gawain and the Green Knight is so different from modern English that it requires translation, because the Gawain-poet was writing in the dialect of the West Midlands region of England, a dialect that subsequently died out.
Almost nothing is known about the anonymous Gawain-poet. No name appears in the manuscript, and although scholars have made numerous attempts to identify the poet with known historical figures, these attempts are no more than educated guesses. The only traits that can be confidently determined about the Gawain-poet are what can be deduced from the poems. The poet was probably male, because there were extremely few female poets at that time. His language places him somewhere in the northwest of England; Cheshire has sometimes been suggested as his home. He was clearly well-educated, and his use of source materials shows that he understood Latin and French. Because the Church was the main source for education at this period, he might have received training to become a member of the clergy. The poems display a thorough knowledge of Christian doctrine and practice, but the poet would not have to have been a practicing clergyman to have possessed such knowledge. The Gawain-poet's intimate knowledge of the details of aristocratic life, such as weapons, feasting, and hunting, indicates that he was either a nobleman himself or attached to a noble house in some way, perhaps writing for a noble patron. A few tantalizing personal details seem to appear in Pearl, in which the poet, speaking in first person, is mourning the death of a young girl, apparently his daughter, who was less than two years old. However, even this detail may be deceptive: Poets could write first-person laments for their patrons' loved ones. (Chaucer did so in his Book of the Duchess.)
Sir Gawain and the Green Knight belongs to a movement known as the Alliterative Revival. Alliterative verse is an extremely old Anglo-Saxon poetic form; the Old English epic Beowulf is written in alliterative verse. As the name implies, alliteration (the repetition of sounds at the beginning of words) is used to provide structure to the poetic line. Alliterative verse is usually unrhymed and does not have a fixed number or pattern of stressed and unstressed syllables. Alliterative verse had never completely died out in Britain, but by the Gawain-poet's time, the regular, rhymed lines characteristic of French and Latin verse were far more influential, and poetry of Italian writers was also beginning to shape English verse. However, the late 1300s saw the production of a large group of alliterative poems, many of extremely high quality. Besides the Gawain-poet's works, the Alliterative Revival includes such works as William Langland's Piers Plowman, John Clerk of Whaley's Destruction of Troy, the anonymous political satire Winner and Waster, the Parliament of the Three Ages, and the Alliterative Morte Arthure (like Sir Gawain and the Green Knight, an Arthurian tale). The poems of the Alliterative Revival were all written by well educated and possibly clerical poets, share themes of high moral seriousness, and use northern and western English dialects. All were the work of provincial poets, living far from Chaucer's cosmopolitan London. The Alliterative Revival's use of native English poetic forms suggests an appeal to English patriotism and national identity, as well as an attempt to distinguish English poetry from its more influential French competitors. Rich description of natural settings and the use of vivid, realistic detail are two other distinguishing features of the Alliterative Revival, and Sir Gawain and the Green Knight is a prime example of both. All of the Gawain-poet's works are notable for their extreme attention to detail, whether of settings or of activities. In general, the Gawain-poet's works are more elegant and polished than the rest of the Alliterative Revival, indicating that they were intended for a cultured and refined audience.