Giovanni Giustiniani was a Genoese captain during the Middle Ages. He was reputed to be one of the bravest and most effective soldiers of his day. He led 700 men to the defense of Constantinople against the Ottoman army of Sultan Mehmed in 1453. Guistiniani was wounded by an Ottoman cannon while defending the walls of Constantinople with Emperor Constantine of the Byzantine Empire. Some sources say the wound was caused by a crossbow bolt. Whatever it was, the projectile pierced his armored gauntlet and mangled his hand. Giustiniani was in great pain, lost his morale and left Constantinople, despite the entreaties of the Byzantine Emperor.

Seeing the demoralization and confusion, Sultan Mehmed II ordered a renewed assault that defeated the Byzantines and Constantinople was taken by the Turks. Although Giustiniani's men managed to escape with their general on board vessels fleeing Constantinople after its fall, the Italian general died of the effects of the wound in the early days of June 1453.