At length he determined to send for help to King Angys, which he forthwith did, promising him half the kingdom if he would come to his aid. So Angys returned again with many men and ships, and by his aid Britain was subdued by force of arms. But though the war ceased there was no peace in the land; and Fortager went about in deadly fear, first of the Britons whom he had betrayed, and next of Angys, lest with his powerful host he should seize the whole kingdom. And lastly, he feared that the men of Brittany would come over and fight for Aurilis-Brosias and Uther-Pendragon, and bring them back to their father's throne. So he determined to build a strong castle, made of well-hewn stone and timber--an impregnable fortress with lofty towers and battlements, a deep moat and heavy drawbridge--such as had never been seen for strength in the world before; and he decided to rear it on Salisbury Plain, and so be surrounded by wastes of land, and far from his foes. At daybreak three thousand men began the work--hewers of wood and carpenters and masons and cunning workers in stone. The foundations were laid deep, on vast blocks of stone clamped with iron; and by nightfall the wall had risen breast-high. But when they came to their work next morning, they found to their dismay that the ground was scattered with the stones they had built up, and that all they had done was destroyed. That day they built it up again, laying the foundations deeper than before, and clamping each stone to the next with iron. But when they came next morning all was overthrown as before. Then Fortager called together ten wise men, and shut them in a tower, open to the sky, that they might read the stars, and find out why these things should be. And after nine days the wise men came to him, and said: "Sire, we read in the stars that an elf child has been born in Britain, knowing things past and things to come. Find the child, and slay him on this plain, and mix the mortar with his blood, and so shall the wall stand fast." So Fortager sent men forth to journey far and wide till they should find the child, and after wandering for many days and weeks, one party of messengers came to a certain town, and found some children quarrelling in the market-place at their games. "Thou son of a black elf," they heard one say, "we will not play with thee, for we know not who thou art." The messengers gazed hard at the five-year-old child thus addressed; and immediately the boy, who was called Merlin, ran up to them, and said: "Welcome, O messengers, and behold him whom you seek. But think not, for all men may say, that my blood will ever make firm the castle walls of Fortager; for his wise men who try to read the stars are but blind, and they blunder past what lies at their very feet." Then the men wondered greatly, and said: "How didst thou know of our errand?"