During theFirst World War (1914–1918),Denmark maintained itsneutrality. The position of neutrality was agreed to by all the major political parties.[1]
Denmark maintained trade with both sides of the war, and was among several neutral countries that exportedcanned meat to the German army. Danish speculators made fortunes on canned meat products, which were often of mediocre quality, while 275 Danishmerchant ships were sunk, and approximately 700 Danish sailors perished during the war.[1]
At the outbreak of war, Denmark mobilized around 50,000 reservists to manCopenhagen's fortifications. This was about half the force that Denmark was expected to mobilize in case of war. By limiting its mobilization and calling the mobilized units "security forces" (Sikringsstyrken), the Danish government was trying to reassure the major powers that it was not intending to join the war.[2][1]
An additionalTunestillingen ("Tune Line") defense installation was constructed during the war. It stretched fromKøge Bay and toRoskilde Fjord. The war brought to the fore the fact that Copenhagen's old fortifications from the 1880s and 1890s were obsolete and too near the capital to protect it from modern artillery bombardment.[3][1]
The Danish government bowed to pressure fromGermany, and hadnaval mines laid in Danish waters with tacitBritish acceptance, despite the fact that Denmark was obliged underinternational law to keep its territorial waters open.[1]
The Germans had already begun to mine Danish territorial waters in order to protect Germany from a British naval offensive. By mining its own waters, the Danish government sought to avoid giving Germany a pretext for an occupation.[1]
During the war, more than 30,000 ethnically Danish men from theSouthern Jutland region in the PrussianProvince of Schleswig-Holstein served in the German armed forces. In total, about 5,300 men from Southern Jutland fell during the war.[1]A Danish military cemetery exists for soldiers fallen whilst fighting for Germany in the French commune ofBraine in France.[4] 79 Danish soldiers are buried there.[5]
Imperial German NavyZeppelins operated out of a base atTønder, which was then part ofGermany, until the base was attacked and destroyed by theRoyal Navy andRoyal Air Force in theTondern raid of 19th July 1918. This was the only major allied raid on ethnically Danish Southern Jutland in the war.[6]
After the conclusion of the war, the1920 Schleswig plebiscites were held in German territory in compliance with theTreaty of Versailles.Northern Schleswig was awarded to Denmark after 74.9% of the territory's population voted in favor of joining Denmark.