The Death-song of Erof.
The Book of Taliesin XL.
From The Four Ancient Books of Wales

WERE changed the elements
Like night into day,
When came the gloriously-free,
Ercwlf chief of baptism.
Ercwlf said,
That he valued not death.
Shield of the Mordei
Upon him it broke.
Ercwlf the arranger,
Determined, frantic.
Four columns of equal length;
Ruddy gold along them.
The columns of Ercwlf
Will not dare a threatening,
A threatening will not dare.
The heat of the sun did not leave him.
No one went to heaven
Until went he,
Ercwlf the wall-piercer.
May the sand be my covering,
May the Trinity grant me
Mercy on the day of judgment,
In unity without want.

"Ercwlf" is Hercules.  Interestingly enough, Hercules is equated with Ogmios, the god credited with inventing ogham, the Celtic alphabet, and with John the Baptist, which may explain "Ercwlf chief of baptism."

However, "Erof" is never mentioned in this poem, but in the poem following it.