Leonardo da Vinci’s early design for a military vehicle with sloped armor was an armored tank.
Leonardo drew the fighting vehicle in the late 15th century, probably while seeking employment from Ludovico Sforza, Duke of Milan. The conical, turtle-like vehicle had sloping armor intended to deflect projectiles and several light cannons pointing through openings around its perimeter.
The vehicle was planned to be moved by people turning internal cranks connected to wheels. Its design could carry a crew and provide protection while advancing across a battlefield. It was never built for Renaissance warfare, and the surviving drawing does not prove that Leonardo intended a fully practical prototype.
A common mix-up is calling it the first modern tank. Modern tanks require engines, tracks, and coordinated military systems, all developed centuries later. Leonardo’s machine is better described as an early armored fighting-vehicle concept.