Regardless if one believes in Arthur or not, he was known to the British and the Welsh. Here are a couple of links to investigate further. The first is about some of the historical and mythical places from the legend. The second is an excellent source of Welsh poetry, some mentioning Aurthur and Merlin (Myrddin).

http://panther.bsc.edu/~arthur/arthu...l#anchor228123

http://www.maryjones.us/ctexts/bbcindex.html

Here is one that I particularly liked that may give some insight to how battles went during the dark ages.

The Dialogue of Myrddin and Taliesin
The Black Book of Carmarthen I

Myrddin:
How sad with me, how said,
Cedfyl and Cadfan are fallen!
The slaughter was terrible,
Shields shattered and bloody.

Taliesin:
I saw Maelgwn battling--
The host acclaimed him.

Myrddin:
Before two men in battles they gather
Before Erith and Gwrith on pale horses.
Slender bay mounts will they bring
Soon will come the host of Elgan.
Alas for his death, after a great joy!

Taliesin:
Gap-toothed Rhys, his shield a span--
To him came battle's blessing.
Cyndur has fallen, deplorable beyond measure
Generous men have been slain--
Three notable men, greatly esteemed by Elgan.

Myrddin:
Again and again, in great throngs they came,
There came Bran and Melgan to meet me.
At the last, they slew Dyel,
The son of Erbin, with all his men.

Taliesin:
Swifly came Maelgwn's men,
Warriors ready for battle, for slaughter armed.
For this battle, Arderydd, they have made
A lifetime of preparation.

Myrddin:
A host of spears fly high, drawing blood.
From a host of vigorous warriors--
A host, fleeing; a host, wounded--
A host, bloody, retreating.

Taliesin:
The seven sons of Eilfer, seven heroes,
Will fail to avoid seven spears in the battle.

Myrddin:
Seven fires, seven armies,
Cynelyn in every seventh place.

Taliesin:
Seven spears, seven rivers of blood
From seven chieftains, fallen.

Myrddin:
Seven score heroes, maddened by battle,
To the forest of Celyddon they fled.
Since I Myrddin, am second only to Taliesin,
Let my words be heard as truth.