In this poem I took some liberties with the legends about Merlin, whose end came because he fell in love with a powerful sorceress, in some versions the Lady of the Lake, and in order to escape his attentions she locked him, or tricked him into locking himself, in either a tower or a menhir, one of the mysterious standing stones that are found all around the coast of Brittany. Long before, Merlin had trained Morgana le Fay, a protegee/student magician(ess?) who "goes bad" and becomes King Arthur's magic foe. (Also, Merlin's experience of time was reported in some myths to be "backwards" -- i.e., the future was his past.)
(Dear God, is anyone going to really bother reading all this??? Oh well, here goes)

I. Merlin Considers Mad Morgana

His magic hands could heal her, they both knew it.
But the magic was withheld. She was too mad, mad with need,
Too sick for his taste. He hadn't meant to trigger
So deep and wild a need;
A transfiguring need, that stripped all loveliness,
Muddied all beauty, like some obscene graffitti of the soul.
He took aim with his eyes, coolly so that no light
Might blur his view of that fevered, foaming soul,
That madness which his hands could heal.

But even his hands cannot touch without feeling,
And who could know what that madwoman's skin
Might unleash in him?

Mad though she was, she understood
The wizard's loneliness, his isolation,
The problems of living backwards, and among men.
Once in some other time he had spoken to her often
Of these and many other things, and they had laughed.
He was so fond of her then! She had shown promise and wit,
And her dark eyes were deep to her heart, spilling the heart and hope's
Gratitude, merriment, all at his feet, all in his trust.
But now -- she was writhing mad, and there were risks.
Risks to these primitive men, and his especial ward.
And his own risk. Was she the foretold foe?
That other time was packed away now and he
Must hold his power all alone, must bear
The icy seclusion of vicarious rule
Among this childlike tribe.

She was of his race, perhaps. Perhaps some kin.
But she had bad blood, or bad stars.
He clasped his magic hands behind.
He shook his bearded head.

II. Afterword

"Was Merlin ever slain? And did he die?"
No. Somewhere stands a rock with a quick eye.
He loved to desperation, Merlin did.
The lady had no choice, no way to rid
Herself of his obsequious attention
But to lock him into magical detention.
He's alive and buried by his own spell
In some stone in Brittany. Who can tell?
So many rocks stand sentry on that rock-infested coast.
Any silent one might be his crypt, his silent host.