The Kriegsmarine (ˈkʁiːksmaˌʁiːnə, War Navy) was the navy of Germany from 1935 to 1945. It superseded the Imperial German Navy of the German Empire (1871–1918) and the inter-war Reichsmarine (1919–1935) of the Weimar Republic. The Kriegsmarine was one of three official branches, along with the Heer and the Luftwaffe, of the Wehrmacht, the German armed forces from 1935 to 1945.
In violation of the Treaty of Versailles, the Kriegsmarine grew rapidly during German naval rearmament in the 1930s. The 1919 treaty had limited the size of the German navy and prohibited the building of submarines.
Kriegsmarine ships were deployed to the waters around Spain during the Spanish Civil War (1936–1939) under the guise of enforcing non-intervention, but in reality supporting the Nationalists against the Spanish Republicans.
In January 1939, Plan Z, a massive shipbuilding program, was ordered, calling for surface naval parity with the British Royal Navy by 1944. When World War II broke out in Sept