シュレースヴィヒ＝ホルシュタイン問題
The First Schleswig War () or Three Years' War () was the first round of military conflict in southern Denmark and northern Germany rooted in the Schleswig-Holstein Question, contesting the issue of who should control the Duchies of Schleswig and Holstein. The war, which lasted from 1848 to 1851, also involved troops from Prussia and Sweden. Ultimately, under international pressure, the Prussians had to withdraw their forces. As a result, the war ended in a Danish victory over the rebels and the signing of the London Protocol in 1852. A second conflict, the Second Schleswig War, erupted in 1864.