h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

One part of the myth sounds quite familiar to the story of Sir Gawain and the Green Knight.

http://www.bbc.co.uk/dna/h2g2/A532270

Both Cuchulainn and Gawain are challenged by a giant (The Green Knight was supposedly rather large) to cut of his head and be prepared to have his own head cut off by the giant at a later date.

There are differences in the story. The story of Gawain (at least the versions I've read) is more complicated. Gawain not only has to deal with a seemingly immortal knight, but also the affections of a lusty noblewoman. He is also not quite as brave as Cuchulainn because he tries to protect himself with a magic girdle given to him by said, lusty noblewoman. Because of this (albeit slight) lack of faith Gawain returns to court at Camalot a chastened man (or maybe he was just embarrassed to have been caught wearing women's underwear).

Does anyone know anything about the link between the two stories. Was one of them inspired by the other? Or were decapitation contests a fairly common thing back then?

I don't know of any specific connection, but the Welsh and Irish myths and legends are all from the same source if you go back far enough. As the Arthurian legends stem from Welsh legends (with quite a bit of French addition) it's quite likely from a common source.

I think that the tale of Gawain was quite probably pilfered from the original Irish tale by romantic medieval minstrels whilst travelling. The tale was then anglicised and transferred to written page rather than word of mouth. Appealing to the people at the time with mostly gore but a bit of romance for the ladies at court, I think it was a firm favourite.

And even a bit of cross-dressing. Gawain and the Green Knight has everything!

I think the idea of someone getting their head chopped off by this green knight guy was probably in common parlance at the time, and then it was adapted by different people to fit their chosen hero. The same thing has happened before with King Arthur stories stealing from other sources.

After all, with no copyright, who's going to stop you?