LEONARDO da Vinci
(b. 1452, Vinci, d. 1519, Cloux, near Amboise)

Giant Crossbow

1480-82
Drawing
Biblioteca Ambrosiana, Milan

From the Codex Atlanticus.

This is a gigantic crossbow. It's difficult to know whether it would have worked, or whether it would have been superior to cannons of the same period. The idea is fascinating.