Leonardo da Vinci described the architronito as a steam cannon intended to propel a cannonball.
The weapon appears in Leonardo’s notes as a proposed form of artillery. His description calls for water to be heated inside a cannon, creating steam pressure that would drive a projectile from the barrel. The concept reflects Leonardo’s interest in converting heat and water into mechanical force.
The architronito is generally treated as a design or speculative project rather than a proven weapon. There is no reliable evidence that Leonardo built and successfully fired a working steam cannon. Renaissance artillery normally relied on the explosive gases produced by gunpowder, not steam.
The name is sometimes translated as “Architonnerre” or “architronito,” so spellings vary between sources. It should not be confused with Leonardo’s multi-barrel organ gun, which used repeated gun barrels rather than steam.