A late 17th-century Virgin has been revealed by Aleksei Khetagurov, chief of icon restoration for the State Historical Museum in Moscow.

She had arrived in his studio as a small, blackened board, slightly warped as many Russian Orthodox icons are, hidden behind her forbidding veil of spoiled dark patina.

"At first I had no idea what was there," said Mr. Khetagurov. He showed a photograph of the icon as it had come to him, dark and murky as though the Virgin were huddling with her child against a storm. "What do you see?" he said. "You don't see anything. You only find out what is there when you uncover it."