In his memoirs, Albert Speer claimed to have invented the idea, which he referred to as the theory of Ruin Value (Gr. "Ruinenwerttheorie"). It was supposedly an extension of Gottfried Semper's views about using "natural" materials and the avoidance of iron girders. In reality it was a much older concept, even becoming a Europe-wide Romantic fascination at one point. Predecessors include a "new ruined castle" built by the Landgraf of Hesse-Kassel in the 18th century, and the designs for the Bank of England built in the 19th century produced by Sir John Soane. When he presented the bank's governors with three oil sketches of the planned building one of them depicted it when it would be new, another when it would be weathered, and a third what its ruins would look like a thousand years onward.