There's a whole technology of cannon, firearms, that not only involved the making of strong iron or bronze tubes but also developing the methods for making gunpowder and igniting it. The trial and error process employed by early gun-founders and gunsmiths therefore gave armies and navies more possible designs as time went on: the 14th century saw the use of fairly simple cannon that could use an uncertain chemical propellant to throw a stone against the huge target of a castle wall. Simpler, short hand-cannon had come in use by the time of the Hussite Wars, c.1426. By the late 1400's gunpowder was more reliable, matchlock systems had been developed and actual shoulder-fired guns were accurate enough to be used for hunting by Emperor Maximilian I.

Although simple cannon had immediate use in battering down fortresses, shoulder-fired firearms, developed later , were not something that immediately became indispensible to the battlefield. Perhaps the biggest innovator was Emperor Charles V, who subsidized Spanish gunmaking technology with some of the mountain of gold and silver he was getting from the New World. He would deploy more and more arcuebuceros in the Italian Wars of the early 16th c. against the French until at last, in the Battle of Pavia in 1525, they were decisive against the charges of the feared Swiss halberdiers . At this point it became obvious to most European powers that shoulder-fired arms were essential. Pikemen would be used well into the 17th c. ( and in some sense continued as muskets/rifles were equipped with bayonets) but firearms from 1525 were pretty standard equipment for at least part of a European army.

Bert Hall: Weapons and Warfare in Renaissance Europe