Imajin said:
"Dutch Hannover" ruling Denmark? I would think that the Danes wouldn't put up with that arragnement for long.
Not in a 1815 PoD anyway, as popular Danish nationalism then was born and alive. But 1615 or 1515 would probably do, as the marked area then economically and to a large degree linguistically and culturally was coherrent.
But if trying to play along we could have the Danish and a lot of German monarchies collapse in resistance to the democratic movements after 1848. There is no 2nd Slesvig-Holsten War, but in 1866 the Habsburgs try to reinstate law and order in the unruly German republics. In the NW the rebellion is mainly finansed by Dutch merchants. This draws into a long and bloody war eventually including anti-Habsburg rebellions in Italy and Hungary, which also has the French intervene to get their part of the German loot. On the Balkans and Armenia there also follows widespread rebelion against the Ottomans, which in no time has UK, France and Russia to throw themselves upon the already decaying Ottoman Empire. A greek army reaches the Bosperous.
At the London peace conference in 1870 the Habsburgs have to recognise the areas of main resistance as independent nations (i.e. Dutch-Hannover, Italy and Hungary) but also gains some important allies/vasals in NE Germany (Prussia, Saxony and Bavaria). France gets a good chunck of SW Germany. The Ottoman Empire becomes Turkey and is limited to the Asia Minor Peninsula minus Armenia, the rest is divided between the Great powers and the new Great Greece. The Russians simply annex Romania.
In a century or two people interested in alternate histrory will discuss what would have happened if the common cause against the hated Habsburgs hadn't united the NW European peoples. Some point to German, Danish and Dutch nationalism to a large degree was behind the 1848-52 rebellions and wonder how a united Great Germany would have acted. Most believe it would have been a haven of refined art and culture...
Regards
Steffen Redbeard