The legend has it that for three nights in a row, the bishop had had the same strange dream in which he was given the same strange command. For two nights he had ignored it. That night, however, that was impossible. That night his nocturnal visitor, the archangel Michael, had decided to give Bishop Aubert of Avranches a little proof that his dreams were reality: He had reached over and pressed a finger on the bishop's skull. When the bishop awoke, he found he had a hole in his head. Maybe, he thought, he'd better do what the angel had said.
It was the year 708, and, as recorded later in the 9th century text “La Revelation,” St. Michael had ordered the bishop to build a chapel on Mont Tombe, a rocky island at the mouth of the Couesnon River near his town of Avranches, France. The angel did not choose his location at random: It was believed to be in this part of France that St. Michael won his mighty victory, described in Revelation, over the dragon.