Iron Maiden of Nuremberg
(The). An instrument of torture for “heretics,” traitors, parricides, etc. It was a box big enough to admit a man, with folding-doors, the whole studded with sharp iron spikes. When the doors were pressed to these spikes were forced into the body of the victim, who was left there to die in horrible torture. (German, Eiserne Jungfrau.)
One of these diabolical machines was exhibited in 1892 in the Free Trade Hall, Manchester, and in London.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894