Then they drew back to see what he who spoke so would do. He went straight to the tomb where the two brothers had been laid and began to write in the stone itself letters that said, HERE LIES BALIN, THE KNIGHT WITH TWO SWORDS, WHO WITH THE LANCE OF VENGEANCE STRUCK THE DOLOROUS STROKE BY WHICH THE KINGDOM OF LISTINOIS IS GIVEN OVER TO SORROW AND DESTRUCTION.

When Merlin had done this, he stayed on the island a month and more and made various enchantments there. Near the tomb he made a bed so strange that no one could sleep there without losing knowledge and memory, so that he never remembered a thing he had done as long as he stayed on the island.

Post-Vulgate Merlin