For 10 points, identify this issue about who ruled over a historically Danish pair of duchies that are now the northernmost of the Germany's states.
One conflict over this problem culminated with the massacre of forces under General Gerlach at the Battle of Dybbol. The London Protocol of 1852 temporarily resolved one conflict over this entity, which is sometimes called the Three Years War. The 1864 Treaty of Vienna attempted to resolve this problem, as did the Convention of Gastein, which called for an enlargement of the Zollverein. According to Lord Palmerston, of the three people who knew why there was fighting over this issue, one is now dead, one is insane and the third was himself, but he had forgotten the reason why. The cities of Lübeck, Flensburg, and Kiel are at the heart of the geographical entity at the center of this issue, which concerns a region that is in the south part of Jutland. For 10 points, identify this issue about who ruled over a historically Danish pair of duchies that are now the northernmost of the Germany's states.
One conflict over this problem culminated with the massacre of forces under General Gerlach at the Battle of Dybbol.
Schleswig-Holstein Question