After the victory they went to the mountain Killaraus, and arrived at the structure of stones, the sight of which filled them both with joy and admiration. And while they were all standing round them, Merlin came up to them and said, "Now try your forces, young men, and see whether strength or art can do the most towards taking down these stones." At this word they all set to their engines with one accord, and attempted the removing of the Giant's Dance. Some prepared cables, others small ropes, others ladders for the work, but all to no purpose. Merlin laughed at their vain efforts, and then began his own contrivances. When he had placed in order the engines that were necessary, he took down the stones with an incredible facility, and gave directions for carrying them to the ships, and placing them therein. This done, they with joy set sail again, to return to Britain; where they arrived with a fair gale, and repaired to the burying-place with the stones. When Aurelius had notice of it, he sent messengers to all parts of Britain, to summon the clergy and people together to the mount of Ambrius, in order to celebrate with joy and honour the erection of the monument. Upon this summons appeared the bishops, abbats, and people of all other orders and qualities; and upon the day and place appointed for their general meeting, Aurelius placed the crown sepulchre upon his head, and with royal pomp celebrated the feast of Pentecost, the solemnity whereof he continued the three following days. In the meantime, all places of honour that were vacant, he bestowed upon his domestics as rewards for their good services. At that time the two metropolitan sees of York and Legions were vacant; and with the general consent of the people, whom he was willing to please in this choice, he granted York to Sanxo, a man of great quality, and much celebrated for his piety; and the City of Legions to Dubricius, whom divine providence had pointed out as a most useful pastor in that place. As soon as he had settled these and other affairs in the kingdom, he ordered Merlin to set up the stones brought over from Ireland, about the sepulcher; which he accordingly did, and placed them in the same manner as they had been in the mountain Killaraus, and thereby gave a manifest proof of the prevalence of art above strength.

Geoffrey of Monmouth's Historia Regum Britanniae