Extract from the Gododdin
In the Book of Aneirin, ca. 13th Century; possibly as early as sixth century  

He pierced over three hundred of the finest.
He struck at both the center and the flank.
He was worthy in the front of a most generous army.
He gave out gifts from his drove of steeds in the winter.
He fed black ravens [killed many of the enemy] on the wall of the
        fortress, though he was not Arthur.
He gave support in battle.
In the van, an alder shield-wall was Gwawrddur. 

Gereint filius Erbin
In the Red Book of Hergest (c. 1400)

Before Geraint, afflictor of the enemy,
I saw white steeds with fetlocks bloodstained,
and after the battle-cry—grievous death. 

Before Geraint, disinheritor of the enemy,
I saw steeds with fetlocks stained from battle,
and after the battle-cry—grievous reflection. 

Before Geraint, oppressor of the enemy,
I saw steeds, white their skin,
and after the battle-cry—grievous silence. 

At Llongborth I saw wrath
and biers more than many
and men blood-red before the rush of Geraint. 

At Llongborth I saw hewing,
men in battle with heads bloodied
before great Geraint, son of his father. 

At Llongborth I saw spurs
and men who would not retreat before spears
and drinking wine from bright glass. 

At Llongborth I saw the weapons
of men and blood flowing,
and after the battle-cry—grievous burial. 

At Llongborth I saw Arthur
 (brave men hewed with iron),
emperor, ruler of battle-toil. 

At Llongborth were killed Geraint’s
brave men from the Devon lowlands,
but before they were killed, they killed. 

Swiftly there ran under Geraint’s thigh
long-legged horses, fed on wheat,
red, with the rush of speckled eagles. 

Swiftly there ran under Geraint’s thigh
long-legged horses, grain was theirs,
red, with the rush of black eagles. 

Swiftly there ran under Geraint’s thigh
long-legged horses, grain scattering,
red, with the rush of red eagles. 

Swiftly there ran under Geraint’s thigh
long-legged horses, grain consuming,
red, with the rush of white eagles. 

Swiftly there ran under Geraint’s thigh
long-legged horses, with the leap of a stag,
with the roar of a blaze on a mountain waste. 

Swiftly there ran under Geraint’s thigh
long-legged horses, grain greedy,
gray tipped, their hair like silver. 

Swiftly there ran under Geraint’s thigh
long-legged horses, deserving grain,
red, with the rush of blue eagles. 

Swiftly there ran under Geraint’s thigh
long-legged horses, grain their food,
red, with the rush of gray eagles. 

When Geraint was born, open were
the gates of Heaven; Christ gave what was asked—
a noble form, Britain’s glory.

From Eglynion y Beddau “The Stanzas of the Graves”
In the Black Book of Carmarthen (mid-thirteenth century) 

The grave of Gwalchmai in Peryddon
as a reproach to men;
in Llanbadarn the grave of Cynon.

The grave of the son of Osfran at Camlan
after many a slaughter;
the grave of Bedwyr on Tryfan hill.

The grave of Owain son of Urien in a square grave
under the earth of Llanforfael;
in Abererch, Rhudderch the Generous.

A grave for March, a grave for Gwythur,
a grave for Gwgawn Red-sword;
hard to find in the world, a grave for Arthur.