Editing Schleswig-Holstein (section)

====Second Schleswig War====
In 1863, conflict broke out again when Frederick VII died without legitimate issue. According to the [[order of succession]] of Denmark and Schleswig, the crowns of both Denmark and Schleswig would pass to Duke Christian of [[House of Glücksburg|Glücksburg]], who became [[Christian IX of Denmark|Christian IX]]. The transmission of the duchy of Holstein to the head of the (German-oriented) branch of the Danish royal family, the [[House of Schleswig-Holstein-Sonderburg-Augustenburg|House of Augustenborg]], was more controversial. The separation of the two duchies was challenged by the Augustenborg heir, who claimed, as in 1848, to be rightful heir of both Schleswig and Holstein. A common constitution for Denmark and Schleswig was promulgated in November 1863, which was a breach of the 1852 London Protocol. This left Denmark politically isolated and led to the [[Second Schleswig War]], with Prussia and Austria invading once again. This was the [[Second War of Schleswig]]. Denmark achieved some initial victories at the [[Battle of Mysunde (1864)|Battles of Mysunde]], and [[Battle of Sankelmark|Sankelmark]], but these successes were short-lived. The Austrians defeated the Danes at the [[Battle for Königshügel|Königshügel]] and [[Battle of Vejle|Vejle]]. However, it was the Prussians who decided the war by decisively winning the pivotal [[Battle of Dybbøl|Battles of Dybbøl]] and [[Battle of Als|Als]].{{cn|date=September 2024}} 

British attempts to mediate in the [[London Conference of 1864]] failed. With the peace [[Treaty of Vienna (1864)]], Denmark was forced to cede Schleswig, Holstein and [[Saxe-Lauenburg|Lauenburg]] to Prussia and Austria. Prussia wished to annex the conquered territories but Austria insisted they be held as [[condominium]]s. This disagreement led to the 1865 [[Gastein Convention]], which, despite their {{lang|la|[[casus belli]]}} being the defence of the German-speaking Schleswig-Holsteiners' wish to remain unified, granted Schleswig and Lauenburg to Prussia and Holstein to Austria. However, this situation did not last long.