King Vortigern the usurper sat upon his throne in London, when, suddenly, upon a certain day, ran in a breathless messenger, and cried aloud-
"Arise, Lord King, for the enemy is come; even Ambrosius and Uther, upon whose throne thou sittest-and full twenty thousand with them-and they have sworn by a great oath, Lord, to slay thee, ere this year be done; and even now they march towards thee as the north wind of winter for bitterness and haste."
At those words Vortigern's face grew white as ashes, and, rising in confusion and disorder, he sent for all the best artificers and craftsmen and mechanics, and commanded them vehemently to go and build him straightway in the furthest west of his lands a great and strong castle, where he might fly for refuge and escape the vengeance of his master's sons-"and, moreover," cried he, "let the work be done within a hundred days from now, or I will surely spare no life amongst you all."
Then all the host of craftsmen, fearing for their lives, found out a proper site whereon to build the tower, and eagerly began to lay in the foundations. But no sooner were the walls raised up above the ground than all their work was overwhelmed and broken down by night invisibly, no man perceiving how, or by whom, or what. And the same thing happening again, and yet again, all the workmen, full of terror, sought out the king, and threw themselves upon their faces before him, beseeching him to interfere and help them or to deliver them from their dreadful work.
Filled with mixed rage and fear, the king called for the astrologers and wizards, and took counsel with them what these things might be, and how to overcome them. The wizards worked their spells and incantations, and in the end declared that nothing but the blood of a youth born without mortal father, smeared on the foundations of the castle, could avail to make it stand. Messengers were therefore sent forthwith through all the land to find, if it were possible, such a child. And, as some of them went down a certain village street, they saw a band of lads fighting and quarrelling, and heard them shout at one-"Avaunt, thou imp!-avaunt! Son of no mortal man! go, find thy father, and leave us in peace."