At last he had recourse to magicians for their advice, and commanded them to tell him what course to take. They advised him to build a very strong tower for his own safety, since he had lost all his other fortified places. Accordingly he made a progress about the country, to find out a convenient situation, and came at last to Mount Erir, where he assembled workmen from several countries, and ordered them to build the tower. The builders, therefore, began to lay the foundation; but whatever they did one day the earth swallowed up the next, so as to leave no appearance of their work. Vortigern being informed of this again consulted with his magicians concerning the cause of it, who told him that he must find out a youth that never had a father, and kill him, and then sprinkle the stones and cement with his blood; for by those means, they said, he would have a firm foundation. Hereupon messengers were despatched away over all the provinces, to inquire out such a man. In their travels they came to a city, called afterwards Kaermerdin, where they saw some young men, playing before the gate, and went up to them; but being weary with their journey, they sat down in the ring, to see if they could meet with what they were in quest of. Towards evening, there happened on a sudden a quarrel between two of the young men, whose names were Merlin and Dabutius. In the dispute, Dabutius said to Merlin: "You fool, do you presume to quarrel with me? Is there any equality in our birth? I am descended of royal race, both by my father and mother's side. As for you, nobody knows what you are, for you never had a father." At that word the messengers looked earnestly upon Merlin, and asked the by-standers who he was. They told him, it was not known who was his father; but that his mother was daughter to the king of Dimetia, and that she lived in St. Peter's church among the nuns of that city. CHAP. XVIII.--_Vortigern inquires of Merlin's mother concerning her conception of him._