Savolax (Savo in modern finnish) is a province in southeastern Finland. Out of all Finnish infantry units the men of Savolax infantry regiment were most actively present in the key events of Swedish king’s German campaign. After the military reform of 1626 there was seven Finnish infantry regiments in Swedish army, all named after the province whose population they were drawn from. Not all these regiments were used in the German campaign (or at least it’s most active early phase) and many units served mostly as garrisons in Northern Germany, Prussia and Livonia. When Swedish field army marched far south to Bavaria and fought the big decisive battles, Finnish infantry was mainly represented by Savolax infantry who also are the ones being most often mentioned in contemporary sources. Men of Savolax regiment performed well especially in the battle of Rain (crossing the Lech river).
Five out of the eight companies in Savolax regiment were sent to Germany with the king. These companies were formed into a regiment under the command of colonel Klas Hastfer even though the Savolax regiment itself was still commanded by general Gustav Horn (who himself was acting as a Field Marshal of the Swedish army). Later the Hastfehr’s regiment was commanded by Lt.Col. Kaspar Ermes who was a veteran captain from Savolax regiment. Even though Swedish conscription system worked on a regional basis and every conscript regiment had a provincial identity, name and insignia, on field of war the regimets were still named after their leader: so Savolax regiment in Germany was usually called “Hastfer’s Finnish regiment” and later “Ermes’s Finnish Regiment”. Last men of Savolax reximent left Germany in 1649, after the peace treaty. Many of those who survived were then transferred to new wars against Poland and Denmark.
It is safe to assume that Savolax was equipped as other native Swedish infantry units. Savolax regiment is the only Finnish infantry unit from the period that we have a reasonably trustworthy, even though only partial, source for a flag. German monk Reginbaldus Möhner painted flags of Swedish forces occupying Augsburg in 1634 and amongst these paintings there are four flags -shown as mere rags- of Kaspar Ermes’s Finnish infantry.