the knightliest creature that Christendom has known
of bearing, of boldness, of brutal expression
the most chivalrous knight to ever come beneath Christ.
How can he go on like that before the emperor? Isn't this a bad idea — especially if he wants to keep his head?
Of course, but the years preceding the appearance of "The Death of King Arthur" were especially dark times for the English people, and such praise for an idealized ruler speaks to those times. The bitterness is between the lines.
France's Charles V hammered at English forces as the Hundred Years' War continued; the English people at home were also hammered by high taxes and unpopular rulers. Discontent exploded in a peasant uprising of the early 1380s. The territory of Gascony — a part of the English claim to French lands — was in a tug of war between French and English forces. And don't forget, presiding over this period was Richard II, an ineffectual monarch to some historians in handling such crises.
This was the world, then, in which the Arthur poem emerged. That explains (to me, at any rate) why it contains so much feverish, elaborate praise of Arthur and his knights and so many celebrations of their unified military courage. The poem yearns for a reality that didn't exist.
"The Death of King Arthur" is a 4,000-line prayer for better days.
As Armitage points out, the poem also seeks to replace the great Arthurian legends of a French chronicler, Chretien de Troyes, with something written by an English hand. That is why there is little here of Guinevere and Lancelot and no mention of the Grail or the Lady in the Lake — major elements in Chretien's romances.
Instead, as we follow Arthur's forces into French territory, the king fights a cannibalistic ogre and there are countless skirmishes between the sides before Arthur and Lucius, finally, lock swords:
Our bold King spun about with the sparkling bridle
and rode within reach to run him through,
piercing mail and man with his mighty sword,
opening him slantwise from his Adam's apple.
So ended the Emperor at Arthur's hands,
And his fellows and friends looked on afraid.
Lucius is no match for the sword Caliburn, Arthur's mighty "wepen" (otherwise known as "Excalibur"). With the emperor slain, Rome now belongs to him, right?
The poem's title supplies the answer. Of course not. Treachery in England forces Arthur — after a strange dream about the Wheel of Fortune — to rush home and confront Mordred, who "has worked great wickedness since [the king] went away." His nephew has claimed the crown — and Guinevere too — and you can't help feeling that the poem's author had no troubles drawing this villainous leader from real life.