It was suggested by a dream from which he said he waked one morning, and of which “all I could recover was, that I had thought myself in an ancient castle (a very natural dream for a head like mine, filled with Gothic story), and that on the uppermost banister of a great staircase I saw a gigantic hand in armour. In the evening I sat down and began to write, without knowing in the least what I intended to say or relate.”