With a POD after the Napoleonic Wars, have the Nordic states reunite again into a single nation, with a relatively stable and effective government. It must survive up to the ATL present day.
This is tough, but how about King Charles XIII named his Danish contemporary as the next Swedish monarch.... at a gunpoint?
Pan-Scandinavianism was quite big during the mid-1800s. The movement essentially died when Sweden-Norway rejected to assist Denmark in the Second Schleswig War of 1864. If you can get Sweden-Norway to support Copenhagen in that war (which should be possible but I'm no Scandinavia expert), then Pan-Scandinavianism survives and might unify the three kingdoms somewhere around the 1880s/90s, I reckon.
What would motivate the Swede-Norwegians to stick their neck out like that, though? They are facing down the entire German Confederation, basically. I imagine you'd need British support to really make it work, or have the Prusso-Austrian power levels much lower.
If Bernadotte's candidacy for election to Swedish King had fallen through in 1808, then maybe a prince of Denmark might get the job.
Iirc a member of the House of Augustenbrg was initially chosen as Crown Prince, but died before the King and Bernadotte was chosen.
Had the Augustenburgs kept the throne, maybe they would also have been chosen for the Danish one instead of the Glucksburgs.
Iirc a member of the House of Augustenbrg was initially chosen as Crown Prince, but died before the King and Bernadotte was chosen.
Had the Augustenburgs kept the throne, maybe they would also have been chosen for the Danish one instead of the Glucksburgs.