The Swedish field artillery was created during the Thirty Years' War (1618-1648) by the great military reformer king Gustav II Adolf. Following the Dutch pattern he established the unification of all artillery cannon calibers. The king also created regimental artillery which operates in battle formations with infantry. These Reforms had excellent results. Starting from the battle of Breitenfeld (1631) the Swedish field artillery became the decisive factor for many of Gustav II Adolf victories.
The Swedish cannons were manufactured with remarkable quality, especially the iron ones. Christopher Polhem, a Swedish scientist and industrialist, created perfect sights and instruments for vertical aiming