The history of Schleswig-Holstein consists of the corpus of facts since the pre-history times until the modern establishing of the Schleswig-Holstein state.
The First Schleswig War, also known as the Schleswig-Holstein Uprising and the Three Years' War, was a military conflict in southern Denmark and northern Germany rooted in the Schleswig-Holstein Question: who should control the Duchies of Schleswig, Holstein and Lauenburg, which at the time were ruled by the king of Denmark in a personal union. Ultimately, the Danish side proved victorious with the diplomatic support of the great powers, especially Britain and Russia, since the duchies were close to an important Baltic seaway connecting both powers.
The Second Schleswig War, also sometimes known as the Dano-Prussian War or Prusso-Danish War, was the second military conflict over the Schleswig-Holstein Question of the nineteenth century. The war began on 1 February 1864, when Prussian and Austrian forces crossed the border into the Danish fief Schleswig. Denmark fought troops of the Kingdom of Prussia and the Austrian Empire representing the German Confederation.
The Danevirke or Danework is a system of Danish fortifications in Schleswig-Holstein, Germany. This historically important linear defensive earthwork across the neck of the Cimbrian peninsula was initiated by the Danes in the Nordic Iron Age about AD 650. It was later expanded multiple times during Denmark's Viking Age and High Middle Ages. The Danevirke was last used for military purposes in 1864 during the Second War of Schleswig.
The Battle of Sehested was fought on 10 December 1813 during the Dano-Swedish War of 1813–1814 between a Dano-Norwegian army under Prince Frederik of Hesse and a Coalition force led by Ludwig von Wallmoden-Gimborn. Near Sehested, Holstein, Frederik's troops defeated the Coalition army, inflicting over 1,100 casualties on von Wallmoden-Gimborn's force while suffering only 500. However, this victory did not prevent the Coalition from emerging victorious in the conflict in 1814.
The Great Northern War was the war fought between a coalition of Denmark–Norway, Russia and Saxony-Poland on one side and Sweden on the other side from 1700 to 1721. It started by a coordinated attack on Sweden by the coalition in 1700, and ended 1721 with the conclusion of the Treaty of Nystad, and the Stockholm Treaties. As a result of the war, Russia supplanted Sweden as the dominant power on the shores of the Baltic Sea, becoming a major player in European politics.
The Battle of Dybbøl was the key battle of the Second Schleswig War, fought between Denmark and Prussia. The battle was fought on the morning of 18 April 1864, following a siege that began on 2 April. Denmark suffered a severe defeat which – with the Prussian capture of the island of Als – ultimately decided the outcome of the war, forcing Danish cession of the duchies of Schleswig and Holstein.
The Military timeline of Denmark is centered around an involvement in wars in Northern Europe since 793 and, recently, elsewhere.
The Battle of Als was fought on 29 June 1864 during the Second Schleswig War between Denmark and Prussia. It was the last major engagement of the war, as the Prussians under General Herwarth von Bittenfeld secured the island of Als – occupied by 9,000 Danish troops, including the garrison of Dybbøl which had retreated there – in a night attack masterminded by the Chief of Staff Leonhard Graf von Blumenthal.
Adolf Hitler invasion of Denmark, was the German attack on Denmark on 9 April 1940, during the Second World War. The attack was a prelude to the invasion of Norway.
The Battle of Fredericia was fought between soldiers of Schleswig-Holstein and Denmark on 6 July 1849 at Fredericia in Denmark. The battle was a part of the First Schleswig War, which was a conflict between Schleswig-Holstein, supported by several German states, and Denmark. The Danes won the battle.
The Battle of Bov was a battle between troops fighting for Schleswig-Holstein, and those for Denmark, which happened on the 9 April 1848 near the town of Flensborg in Denmark, during the First Schleswig War. The Danes won the engagement. It was the first battle of the First Schleswig War.
The Battle of Isted took place on 25 July 1850 near the village of Idstedt, in what is today Schleswig-Holstein, Germany. The battle was part of the First Schleswig War, and is the largest battle ever fought in northern Europe. The Danes won the battle.
The Battle of Bornhöved or Bornhöft took place on 7 December 1813 between a Swedish cavalry regiment,Mörner's Hussar Regiment later Kronprinsens husarregemente or Crown Prince's Hussar Regiment) under Bror Cederström and Prince Frederik of Hesse's Danish troops reinforced by smaller numbers of Polish cavalry and German infantry. The clash occurred at the small village of Bornhöft in what is now Schleswig-Holstein in northern Germany. The engagement occurred during the War of the Sixth Coalition, part of the Napoleonic Wars, and was one of the last time Swedish and Danish forces met on the battlefield.
Karl Wilhelm Freiherr von Willisen was a Prussian general.
The Battle of Sankelmark was a minor battle during the Second Schleswig War. It took place on 6 February 1864 between Sankelmark and Oeversee, on the road between Schleswig and Flensburg, during the Danish retreat from Dannevirke.
The Battle of Schleswig occurred near Dannevirke on Easter morning, 23 April 1848 as the second battle of the First Schleswig War of 1848–1850.
Skirmish of Århus or Rytterfægtningen on 31 May 1849 was a skirmish during the First Schleswig War between Denmark and Prussia under the German Confederation, a few kilometers north of the city of Aarhus, Denmark. The skirmish was a Danish victory that had the effect of stopping the Prussian advance through the peninsula of Jutland at the city of Aarhus.
The Battle of Vejle was a battle of the Second Schleswig War that occurred on March 8, 1864, between the Austrian Empire and Denmark on the town of Vejle. The Austrian victory at the battle opened the way for the Evacuation of Fredericia and the Battle of Jasmund as well as solidifying Ludwig von Gablenz's military career.
The Dano-Swedish War of 1813–1814 also referred to as Charles John’s campaign against Denmark, or as the War for Norway was the Coalition campaign against Denmark-Norway led by the Swedish crown prince Charles John, and it was the last major conflict between Denmark and Sweden. The war was a part of Sweden's campaign against the French Empire, who after defeating at The Battle of the Nations turned its attention to Napoleon's last ally Denmark–Norway. Denmark was invaded through its German duchies, who later became occupied. In the peace treaty Denmark was forced to give Norway to Sweden, ending the 400 year personal union between them.
Duchy of Schleswig 
Duchy of Holstein 
Denmark 
Karl Wilhelm von Willisen