In the years leading up to 1914, Europe was dominated by two alliances between major powers: the Central Powers, comprising Germany, the Austro-Hungarian Monarchy and their allies on the one hand, and the Entente Powers of France, Russia, Great Britain and their allies on the other. Most small nations, such as Denmark, were not included in these alliances.

At that time, Europe was dominated by an aggressive nationalism, unrest in the Balkans and a lack of willingness to negotiate among the major powers. The German government viewed war as unavoidable if Germany was to secure its foreign policy interests and the stability of its domestic policy.

The conflict that subsequently became the First World War was triggered by the murder of the heir to the throne of Austria-Hungary by a Serbian nationalist in Sarajevo on 28 June 1914. Backed by Germany, the Austro-Hungarian Empire immediately issued a range of ultimatums to Serbia – not all of which were met. As a result, Austria-Hungary declared war on Serbia on 28 July. Russia had guaranteed Serbian security and immediately began to mobilise. This led to a chain reaction – and marked the start of the Great War.