A culverin was a relatively simple ancestor of the musket, and later a medieval cannon, adapted for use by the French in the 15th century, and later adapted for naval use by the English in the late 16th century. The culverin was used to bombard targets from a distance. The weapon had a relatively long barrel and a light construction. The culverin fired solid round shot projectiles with a high muzzle velocity, producing a relatively long range and flat trajectory. Round shot refers to the classic solid spherical cannonball.
The term "culverin" is derived from the Latin, colubrinus, or "of the nature of a snake". It was originally the name of a medieval ancestor of the musket, used in the 15th and 16th centuries.
The hand culverin consisted in a simple smoothbore tube, closed at one end except for a small hole designed to allow ignition of the gunpowder. The tube was held in place by a wooden piece which could be held under the arm. The tube was loaded with gunpowder and lead bullets. The culverin was fired by inserting a burning slow match into the hole.
These hand culverins soon evolved into heavier portable culverins, around 40 kg (88 lb) in weight, which required a swivel for support and aiming. Such culverins were further equipped with back-loading sabots to facilitate reloading, and were often used on ships. Many were immobile due to the heavy weight.