The moon in a black vault rides white and high.
Let us go forth, from these most desolate lands,
Led by the spirit's cry."

"You are quite right," said the Wizard. "Your lands will be desolate
unless you help build the invisible wall."

At that all the courtiers whose eyelids had been drooping with the summer
heat and with dreams of romance, looked up, and the Princess Myrtle
withdrew her gaze from Prince Merlin, and fastened her sweet eyes upon
the Wizard. "You must not care what the minstrels sing," she said. "We
are all so happy here, that we love songs of sorrow."

"Sweet Princess," said the Wizard, "King Theophile intends to make war
upon you, and I have come to tell you that already your subjects have
built a fine invisible wall of good deeds and sacrifices; but they must
not perform all the labor and have all the pain while the nobles jest and
feast. For the wall must have a stone in it from every kind of man, rich
or poor, high or low, else it will not endure. And you, the Princess,
must put in the strongest stone of all, since the ruler of a country must
be its protector."

All the courtiers smiled at this, but the Princess did not smile, because
she was as wise as she was fair. She looked down at her peach-colored
robe of satin and her little slippers embroidered with seed-pearls, and
she drew a long-stemmed rose from the jade bowl near her throne to pass
back and forth across her lips, as was her manner when thinking.

"Prince Merlin," she said at last, "if this strange tale be true, what
stone wilt thou place in the invisible wall?"