The Battle of the River Plate was fought in the South Atlantic on 13 December 1939 as the first naval battle of the Second World War. The Kriegsmarine heavy cruiser Admiral Graf Spee, commanded by Captain Hans Langsdorff, engaged a Royal Navy squadron, commanded by Commodore Henry Harwood, comprising the light cruisers HMS Ajax, HMS Achilles and the heavy cruiser HMS Exeter.

The Kriegsmarine was the navy of Nazi 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 It superseded the Imperial German Navy of the German Empire (1871–1918) and the inter-war Reichsmarine (1919–1935) of the Weimar Republic.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.