This house, which was so large as to be fully known to none but some ancient officers who successively inherited the secrets of the place, was built as if suspicion herself had dictated the plan. To every room there was an open and secret passage; every square had a communication with the rest, either from the upper stories by private galleries, or by subterranean passages from the lower apartments. Many of the columns had unsuspected cavities, in which a long race of monarchs had reposited their treasures. They then closed up the opening with marble, which was never to be removed but in the utmost exigencies of the kingdom; and recorded their accumulations in a book, which was itself concealed in a tower, not entered but by the emperor, attended by the prince who stood next in succession.