The Grey Havens

Can anyone tell me what this picture is of?
The annotation only says "Sir Gawain and the Green Knight"
Anybody have any idea who these guys are?
I assume its from Tolkiens work because its on the 1997 calendar but i have never read anything about it.
Any help would be greatly appreciated.

http://www.edoras-art.de/cgi-bin/howe.pl?file=97tcal_11.jpg

Sir Gawain was a knight of the Round Table and nephew of King Arthur. "Sir Gawain and the Green Knight" was a poem written by Tolkien.

P.S.: Anyone trying to access the aforementioned link will get 404 error. You'll have to paste it's URL in the browser window with 404 and press [Enter]. Where there's will, there's a way, I always say. And there's a way around banned remote linking.

Sorry to have to correct you Cirdan (although of course you could have avoided this by providing correct informatin )
Sir Gawain and the Green Knight is a Romance composed in the fourteenth century about Sir Gawains meeting with the Green Knight a poem which Tolkien Translated from the Old English and of which he also made a very groundbreaking analysis in his paper entitled "Sir Gawain and the Green Knight". Since the green knight in the story is a shapeshifter it has been guessed that he is the character upon which Tolkien based the character of Beorn.

Here is a link to a lot of early texts about sir Gawain including his encounter with the Green Knight. Sir Gawain