What is the most likely difference between Sir Gawain and the Green Knight and the legend that originated it?difference

In "Gawain and the Green Knight," Gawain is a young, but
impetuous and untried knight of King Arthur's court who accepts the challenge of the
Green Knight to do battle.  When Gawain loses, he promises that he will meet the Green
Knight in one year so that the Green Knight has the chance to exact his revenge from the
young man.

When Gawain arrives at the agreed upon location,
temptation is placed before him three times in order to test his honor as a true and
loyal knight.  This is the central focus of the story.

The
difference between this popular version and what seems to be the original source of the
story is that "Gawain and the Green Knight" includes medieval values and moral
codes.

The earlier stories are considered "beheading game"
stories that did not focus on the elements of chivalry (knightly virtue, honor and
courtly love) as the "Gawain" story did.  The early stories focused on the battle—the
beheading.

So the primary element that differentiates the
old beheading game stories, and "Gawain and the Green Knight" story is the presence of
chivalry in the second tale.