In 1453, a giant bronze cannon crouched before the Theodosian walls of Constantinople, coughing fire at the Gate of St. Romanus.
Cast by the founder Orban for Sultan Mehmed II, it hurled boulder-shot that chewed stone instead of chipping it.
But the breach came less from one monster gun than from method: Ottoman crews kept whole batteries firing while Byzantine masons patched the walls by lantern.
When St. Romanus finally sagged, stone met industry — and lost.