Heimdal looked at the stranger narrowly, for there was that about him which his sharp eyes did not like. But he made no answer, only blew on his golden horn, which was so loud that it sounded through all the world. At this signal all the Æsir came running to the rainbow bridge, from wherever they happened to be, to find out who was coming to Asgard. For it was Heimdal's duty ever to warn them of the approach of the unknown. "This fellow says he is a builder," quoth Heimdal. "And he would fain build us a fortress in the city." "Ay, that I would," nodded the stranger, "Look at my iron arm; look at my broad back; look at my shoulders. Am I not the workman you need?" "Truly, he is a mighty figure," vowed Odin, looking at him approvingly. "How long will it take you alone to build our fortress? We can allow but one stranger at a time within our city, for safety's sake." "In three half-years," replied the stranger, "I will undertake to build for you a castle so strong that not even the giants, should they swarm hither over Midgard--not even they could enter without your leave." "Aha!" cried Father Odin, well pleased at this offer. "And what reward do you ask, friend, for help so timely?" The stranger hummed and hawed and pulled his long beard while he thought. Then he spoke suddenly, as if the idea had just come into his mind. "I will name my price, friends," he said; "a small price for so great a deed. I ask you to give me Freia for my wife, and those two sparkling jewels, the Sun and Moon." At this demand the gods looked grave; for Freia was their dearest treasure. She was the most beautiful maid who ever lived, the light and life of heaven, and if she should leave Asgard, joy would go with her; while the Sun and Moon were the light and life of the Æsir's children, men, who lived in the little world below. But Loki the sly whispered that they would be safe enough if they made another condition on their part, so hard that the builder could not fulfil it. After thinking cautiously, he spoke for them all. "Mighty man," quoth he, "we are willing to agree to your price--upon one condition. It is too long a time that you ask; we cannot wait three half-years for our castle; that is equal to three centuries when one is in a hurry. See that you finish the fort without help in one winter, one short winter, and you shall have fair Freia with the Sun and Moon. But if, on the first day of summer, one stone is wanting to the walls, or if anyone has given you aid in the building, then your reward is lost, and you shall depart without payment." So spoke Loki, in the name of all the gods; but the plan was his own.