Sir Gawain and the Green Knight by John Howe.
From the poem:
The green knight got ready, feet firm on the ground;
leaned his head a little to let the cheek show,
and raised the rich riot of his hair
so the nape of his neck was naked and exposed.
Gawain held the ax high overhead,
his left foot set before him on the floor,
swung swiftly at the soft flesh
so the bit of the blade broke through the bones,
crashed through the clear fat and cut it in two,
and the brightly burnished edge bit into the earth.
The handsome head fell, hit the ground,
and rolled forward; they fended it off with their feet.
The red blood burst bright from the green body,
yet the fellow neither faltered nor fell
but stepped strongly out on sturdy thighs,
reached roughly right through their legs,
grabbed his graceful head and lifted it from the ground,
ran to his horse, caught hold of the reins,
stepped in the stirrup, strode into the saddle,
the head dangling by the hair from his hand,
and seated himself as firmly in the saddle
as if he were unhurt, though he sat on his horse without
He swiveled his bulk about;
the ugly stump still bled.
They gaped in fear and doubt
because of the words he said.