The Battle of the Atlantic was the longest continuous military campaign of World War II, running from 1939 through the defeat of Nazi Germany in 1945, and was at its height from mid-1940 through to about the end of 1943.
The Battle of the Atlantic primarily pitted the U-boats and armed merchantmen of the German Navy (Kriegsmarine) against Allied convoys. The convoys, coming mainly from North America and the South Atlantic and going to the United Kingdom and the Soviet Union were protected for the most part by the British and Canadian navies and air forces. These forces were later aided by ships and aircraft of the United States. The German U-boats and armed merchantmen were joined by submarines of the Italian Royal Navy (Regia Marina) after Fascist Italy entered the war on 10 June 1940.
