High Quality Content by WIKIPEDIA articles! Cannon operation required specialised crew and gunners, who were first enlisted by the Spanish in the 14th century. The nature of cannon operation often depended on the size of the cannon and whether they were breech-loading or muzzle-loading. English cannon of the late 14th century became mobile, while the largest cannon (such as the heavy siege cannon of the Ottoman Turks or the Jaivana cannon of India) required huge crews to transport and operate them.