She followed him wherever he went, and made countless efforts to learn all his arts and to discover all his magic spells.

In order to beguile the aged Merlin into telling her all she wished to know, Vivian pretended great devotion, which is admirably related in Tennyson's "Idylls of the King," one of which treats exclusively of Merlin and Vivian.
This enchantress even went with him to the fairy-haunted forest of Broceliande, in Brittany, where she finally beguiled him into revealing a magic spell whereby a human being could be inclosed in a hawthorn tree, where he must dwell forever.
"And then she follow'd Merlin all the way, E'en to the wild woods of Broceliande.
For Merlin once had told her of a charm, The which if any wrought on any one With woven paces and with waving arms, The man so wrought on ever seem'd to lie Closed in the four walls of a hollow tower, From which was no escape for evermore; And none could find that man for evermore, Nor could he see but him who wrought the charm Coming and going; and he lay as dead And lost to life and use and name and fame." TENNYSON, _Merlin and Vivien_.
This charm having been duly revealed, the Lady of the Lake, weary of her aged lover, and wishing to rid herself of him forever now that she had learned all he could teach her, lured him into the depths of the forest.
There, by aid of the spell, she imprisoned him in a thorn bush, whence, if the tales of the Breton peasants can be believed, his voice can be heard to issue from time to time.
"They sate them down together, and a sleep Fell upon Merlin, more like death, so deep.
Her finger on her lips, then Vivian rose, And from her brown-lock'd head the wimple throws, And takes it in her hand, and waves it over The blossom'd thorn tree and her sleeping lover.
Nine times she waved the fluttering wimple round, And made a little plot of magic ground.
And in that daised circle, as men say, Is Merlin prisoner till the judgment day; But she herself whither she will can rove-- For she was passing weary of his love." MATTHEW ARNOLD, _Tristram and Iseult_.
[Illustration: THE BEGUILING OF MERLIN .-- Burne-Jones.] According to another version of the tale, Merlin, having grown very old indeed, once sat down on the "Siege Perilous," forgetting that none but a sinless man could occupy it with impunity.

He was immediately swallowed up by the earth, which yawned wide beneath his feet, and he never visited the earth again.
A third version says that Vivian through love imprisoned Merlin in an underground palace, where she alone could visit him.

There he dwells, unchanged by the flight of time, and daily increasing the store of knowledge for which he was noted..