Merlin and The Lady in the lake.

Merlin fell in love with the lady in the lake,
but rejected - her favours he tried to take;
all his potions turned out to be of no avail,
but as a magician he was not allowed to fail.

He visited my world asking for some advice,
said that I know everything of men and mice,
so just tell me how to win this fair lady's hand,
I told him to look in the invisible grains of sand.

What are they?  They are where you have not
looked before - the places where just  time forgot;
when you find them you'll know what was wrong,
only then will she give you all for what you long.

It was done - he could rest in his magic forest land,
dream of her forever while he lay at peace in Broceliande.