"The military virtue of an Army is, therefore, one of the most important moral powers in War, and where it is wanting, we either see its place supplied by one of the others, such as the great superiority of generalship or popular enthusiasm, or we find the results not commensurate with the exertions made.—How much that is great, this spirit, this sterling worth of an army, this refining of ore into the polished metal, has already done, we see in the history of the Macedonians under Alexander, the Roman legions under Cesar, the Spanish infantry under Alexander Farnese, the Swedes under Gustavus Adolphus and Charles XII, the Prussians under Frederick the Great, and the French under Buonaparte." - On War by General Carl von Clausewitz (emphasis mine).

What should be noted here, that Finland during The 30 Year War did not exist as an independent state, but as an Eastern part of The Swedish Empire. Around 40% of one of the most successful fighting force in Europe during The 30 Year War consisted of soldiers conscripted from Eastern parts of The Swedish Empire, area now known as Finland.

There have been several conflicts over the area of Finland involving Finnic tribes, Vikings, Novgorod, Sweden, Kievan Rus. Finnish troops have partaken in several wars as part of Swedish Empire, as well as later on as part of The Russian Empire.

The Finnish Civil War in 1918 left a scar in Finnish history, although the casualties were numerically only 1 percent of the population, the conflict between the Whites and the Reds left a scar in the minds of the nation for generations to come.

During WW2 Finnish troops were highly successful against Soviet forces, the casualties of Soviet Forces being 10 times that of the Finns. Even if Finland lost both Winter War and Continuation War it meant that Russia could only claim a pyrrhic victory and had to handle Finland with more carefully and with relatively soft diplomacy in the subsequent decades compared to other countries in the Soviet sphere of influence.