On receiving this defiant message, Arthur threw himself, with five hundred good men, into a strong tower near Carlion, for he was ill prepared for attack. There he was closely besieged by his foes, but the castle was well victualled, and held out stoutly against its assailants.
During the siege Merlin appeared suddenly among the kings, and told them privately who Arthur really was, assuring them that he was of nobler blood than themselves, and was destined long to remain king of England, and to reduce Scotland, Ireland, and Wales to his sway. Some of the hostile monarchs believed the magician's story, but others doubted it, King Lot of Orkney laughing him to scorn, while some among them called him a prating wizard.
But it was agreed that they should hold a conference with Arthur, they promising if he came out to them to place no hindrance to his safe return. Merlin then sought the king and advised him to accept the conference, telling him that he had nothing to fear. Thereupon Arthur armed himself, and taking with him the Archbishop of Canterbury and several noble knights, went out boldly to meet his foes.
The conference was an angry and bitter one, the kings speaking strongly, and Arthur answering them with stout words of defiance, in which he told them plainly that if he lived he would make them bow to his throne. In the end they parted in wrath, the kings returning to their camp and Arthur to the tower.
"What do you propose to do?" said Merlin to the kings. "If you take a wise man's advice you will withdraw, for I tell you that you shall not prevail here, were you ten times as many."
"We are not the men to be advised by a dream-reader," answered King Lot. "If you are the wise man you say, you will take yourself away." At this reply Merlin magically vanished from among them, and immediately appeared to King Arthur in the tower, bidding him boldly to sally forth and attack his enemies, and trust to fortune and valor for success. Meanwhile three hundred of the best knights of the kings had deserted their ranks and come to join him, much to his comfort, for he had been greatly outnumbered.
"Sir," said Merlin, "fight not with the sword that you had by miracle, till you see things go to the worst; then draw it out and strike shrewdly for your throne."