Military engineering: Sappers using a 'sow', A, to begin excavations outside the walls of a city under siege. B is a wheeled shield with its tough leather protective cover turned back to show its construction. From "Poliorceticon" by Justus Lipsius (Antwerp, 1605). Copperplate engraving. (Photo by: Universal History Archive/UIG via Getty Images)
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Album / Universal Images Group / Universal History Images \ UIG