I noticed that Sweden has been successful in pacifying a bitter rivalry with Denmark overtime. Last time they had a conflict was just 200 years ago. But many other countries still have really rancorous rivalries and ethnic conflicts. It seems like once all external threats have been subdued in one way or another, the population has nothing else to do but to improve their own condition, so Sweden blossoming into what it is now makes sense. But how did they do this? Not only integrating leftover Danes from annexing what is now southern Sweden(Scania most notably), they also had an influx of Walloons 500 years ago, Finns 300 years ago, and in the ancient past Geats & Gutes who were conquered. I haven't been successful in finding any books discussing this, only books talking about who conquered what, who went where, who lived where and facts like that.
Why is it that all of these just integrated into Swedish society and accepted their role as Swedes instead of harboring resentment for hundreds of years such as Serbs in Slavonia against Croatia for instance, or Northern- and Southern Yemenites, Catalonians and Spaniards, or ethnicities in Central Asia which have the same predominant religion and history, same ethnic family(Altaic/Turkic), so many centuries of unity through empires, but still they don't count themselves as, for instance, Kazakhs if they are Uzbeks living in Kazakhstan?
Wrong premises lead to wrong conclusions
First about Croatia - it did not exist as an independent country until 1991. Until 1918 it was part of the Habsburg Monarchy, later Austria-Hungary. After WW1 it was part of the Kingdom of Serbs, Croats and Slovenes, later Yugoslavia. During WW2, it was a German puppet state, so called Independent State of Croatia . Sadly, animosity and hatred towards Serbs was and is part of the Croatian national identity. This was most evident during WW2, when Ustashe movement ruling the Croatia strove to kill, expel or convert any Serb they could find, but continued after the Croatian war of independence when the majority of Serbs living there was forced to flee. Unfortunately, popularity of the Ustashe movement, especially among young Croats is high even today, with incidents against remaining Serbs happening regularly link in Croatian.
Concerning Skåneland or so called Eastern Denmark, Swedes actually did a lot of things Croats later employed against Serbs. Granted, they did neither create concentration camps not they employed murder on a systematic scale, but they did forbid usage of the Danish language, especially in church and official business, appointed Swedes exclusively as priests and civil servants, banned inhabitants of Skåneland from enrolling into Copenhagen University etc… Any rebellion was crushed with brutal force and harsh punishments. Of course, since this happened mostly during the 17th and 18th century, it was not considered as something uncommon. Today, it would be classified as ethnic cleansing and forced assimilation.
As for Finland under Swedish rule, this started in middle ages. Essentially, the ruling class of Finland came from Sweden, while Finns remained largely a subjugated peasant population. The Finnish language did survive, but it was not in official usage. Assimilation did not happen mainly because there were not enough Swedish colonists, and latter the Finish territory came under dispute between Sweden and Russia, with Russia eventually winning and creating the Grand Dutchy of Finland.
There is no formula for this. It's rather the fact that it was a long time since Sweden was involved in a war, that makes swedes reluctant to fight wars. After such long period, aggressions against other nations, tend to fade away.List of site sources >>>