Leonardo da Vinci designed a giant crossbow mounted on a frame as a military machine.
The enormous bow appears in Leonardo’s late-fifteenth-century military studies. Its large scale was intended to produce a powerful shot, while a broad wheeled support would help transport and stabilize it. Leonardo also considered mechanical methods for drawing the bowstring, since a weapon of that size could not be cocked by hand like an ordinary crossbow.
The design reflects the period’s continuing interest in siege artillery and oversized projectile weapons. Leonardo was not simply enlarging a hunting crossbow: he was studying structural strength, leverage, tension, and the handling of a large machine in the field.
The giant crossbow was a proposal rather than a documented battlefield success. It is sometimes confused with ancient Greek and Roman ballistae, which were different torsion-powered weapons. Leonardo’s drawing belongs to the age of gunpowder artillery, when engineers explored both traditional and new ways to project missiles.