The guards regiments, the garrison regiments, and the artillery recruited its soldiers through volunteer enlistment by the regiment itself. Many new regiments of enlisted mercenaries were also raised in wartime; for example, only one-fifth of soldiers in the Swedish army at the Battle of Breitenfeld in 1631 were of Swedish or Finnish origin. The rest of the army was made up of German, Scottish and other European mercenaries. This would however change during the Great Northern War, in which a majority of the regiment's soldiers were from Sweden (including Finland) or its dominions.