From the Guardian: "He had found the route after discovering a forgotten map in public archives which revealed the secret access from the monastery attic. The map was a key exhibit in the trial. The attic, reached by a daring climb up exterior walls, led to a steep, narrow stairway and then the secret chamber. A hidden mechanism opened up the back of one of five cupboards in the library. The plans suggested that the secret route to the library, once the monastery's common room, served in medieval times to spy on the monks' conversations. Inside the library, Gosse spent hours by candlelight picking out volumes, some of which he stored in the attic."