The following poem is, I believe, from the Black Book of Carmathen, a 13th century Welsh text possibly from the priory of St. John in Carmarthen. I tried to give an ethereal feel to the photo,but don't think I succeeded!

Blessed is the birch in the valley of Gwy
Whose branches will fall off one by one, two by two
It will remain when there will be a battle in Ardudwy
And the lowing together of the cattle about the ford of Mochnwy
And spears and shouting at Dyganwy
And Edwin bearing sway in Mona
And youths pale and light
In ruddy clothes commanding them.

Blessed is the birch in Pumlumon
Which will see when the front of the stage shall be exalted
and which will see Franks clad in mail
About the hearth food for whelps
And monks frequently riding on steeds.

Blessed is the birch in the heights of Dinwythy
Which will know when there shall be a battle in Ardudwy
And spears uplifted around Edrywy
And a bridge in the Taw, and another on the Tawy
And another, on account of a misfortun, on the banks of the Gwy
And the artificer that will make it, let his name by Garwy;
and the principle of Mona have dominion over it.
Women will be under the Gynt, and men in affliction
Happier than I is he who will welcome
The time of Cadwaladyr: a song he may sing!

To see others remembering Maire in song, poem and proverb: http://forum.pbase.com/viewtopic.php?f=16&t=47823&sid=43007bc7bde6f9b742565e0da91d6967