Guro'r Glyn was a radical poet in the mid 15th Century. He wrote a poem depicting the life of Ieuan and his family at Cryniarth.

Although the poem has been translated in substance throughout by the Reverend Walter Davies and Reverend John Jones the text is often so obscure that even the translators had difficulty in understanding the rendering. However the poem does confirm the historical status of Cryniarth and the people who lived there (highlighted in pale blue).

The Gentleman of truth and honour,
Whom we praise above any one,
One of the Saints of this Island,
His name is Ieuan, son of Einion,
From the daughter of the noble Rhydderch,
Was gained the race that will enforce preserve us;
From the flower and genius of the South,
And from Gwynedd, even from Einion;
Of the race of the Indeg(1) of Hendwr,
As high or higher than her spouse.
A Blessed Beuno, at the top of the bank(2),
Is Ieuan, the life of us all;
A lamb for peace and reposes,
Yet a line in fury to fell the forward,
Albeit a lamb of God and Saint John,
Not two of the Earls could cary off his share.
He is not the man to despoil the simple,
Nor would his Angharad allow it.
There has been plundering, and no government;
Wrongdoing, - it has over spread the world.
Then Ieuan was the shied of his country,
And upright and true has been Ieuan.
In the faith did Ieuan flee,
With his disciplined force, by calling in David,
As fled the host of Moses From the flood before Pharaoh's men of old.
When Moses essayed the sea It ebbed away with threefold speed,
And then the host of the heathen Entered the flood, but escaped not the mire.
Even so, as with Pharoch's followers,
Do the false drive the faithful away.
The raid and pursuits o'eer the border To us are Noah's flood and its cry.
By grace was Ieuan the man to gain
The ebb's edge, and his children behind him.
To the shore came Ieuan and his host,
To their martyrdom went the others; But seas, for their deadly sin,
Drowned some of those behind him,
As Nazareth of ancient Tribe of Israel,
Of his children is he the benign planet.
Master Richard, who calls upon the Lord,
Is the master of all power.
Up the ladder will I go To call him the eldest of his line.
David makes ready spear-staves for France;
The Saint David of all young barons.
A pleadeeer and advocate he,
The noble pleader of the stem of Giwn.
Rhys, in the foreground of Nannau;
Gruffydd, long life to the twain !
"Birds of the Bright Lake" are they to me.
Of all the tribes of Gwynedd, from the Mausions of the Mead,
And the two youngest brothers after them,
Of their famous line in succession,
Are the Saints, Thomas and John,
That shall preserve Gwnedd, a forest of blessed ones.
Six tall sons, six strong men,
And eight between sons and daughters.
Eight persons came in one house,
And one, the old Noah, from the same:
Eight who are a just society,
Eight souls are the einion family.
Angels of God on the water's brink,
And bulls of battle of the Tribe of Hendwr.
The host of Cryniarth, in Meiarth flowing with mead,
Shall fill every spot in Gwynedd.
A grove engrafted are they, like the orchard;
They are the line of old Edwin.
Vain are substance and fortune
Without the race of Ieuan and his spouse.
And give Thou, O God, long life to the pair,
And to their children and their offspring too,
So as to preserve this selfsame clan
For the land above until the day of doom.

1 - Indeg - According to Welsh mythology - a lovely lady of King Arthur's court.

2 - Cryniarth, on the height above Hendwr, on the bank of river Dee, where an entrenchment is still visible to mark the site. Many vitrified stones, taken from a vallum recently destroyed, are placed in a wall behind it.