Here, does another wild man tame a knightly hero? Perhaps we are closer, at least, to Campbell’s hero (simplified here) but even in the Gawain quest the model is awry.

Into the high feasting of Arthur’s court comes a giant, a knight “oueral enker grene,” an ettin from the wild outside, who sets a challenge: a stroke for a stroke. Gawain boldly accepts and lops off the Green Knight’s  head, only to see the giant pick up his head and leave. Gawain must meet the challenge at the Green Chapel at new year. His lodging, at the end of his quest, in Castle Haudesert, challenges his honour further, as he is approached by the lady of the castle, and with some mauvaise foi, Gawain avoids losing his honour entirely but also compromises it.

At the Green Chapel –  a site of demonic cult, and maybe based on  Ludchurch in the Peaks – he meets his challenger, the Green Knight, and escapes with a nick on his neck and, as part of his just deserts, receives a round exposition of his failings. He returns to Camelot chastened.

The C14th text is a well-trodden path for Middle English scholars, and translations/commentaries are many. The liveliest and most recent version is Simon Armitage’s, which keeps many of the devices of the original poem; his own reading (thanks for this, Mat!) further underlines the “northernness ” of the poem. Bernard O’Donohue, medieval scholar and poet, has a good version with an excellent introduction. Tolkien’s version is on my desk. Wikipedia is awash with footnotes. Interpretation is varied and plentiful.