Karl Doenitz was a German naval officer who built Adolph Hitler's submarine fleet in the 1930s and who became Germany's chief naval officer midway through World War II. The German dictator named Doenitz his successor during the last days of the war in May 1945. Doenitz was charged with war crimes by the Allies after the war and was tried and convicted with other leading National Socialist (Nazi) officials at the Nuremberg trials in 1946.

Doenitz was born on September 16, 1891, in Grunau-Berlin. He joined the Germany navy during World War I and served as a submarine officer in the Black Sea and the Mediterranean. Following Germany's surrender in 1918, the Allies forced Germany to sign the Treaty of Versailles, which sought to prevent Germany from ever again becoming a military power by restricting military spending and construction. The German Navy was severely crippled by these terms, and Doenitz, like many German...