German Grand Admiral Karl Doentiz was born in Prussia. He joined the German Imperial Navy, and in 1916 began specializing in submarine warfare. Doenitz was the commander of the German submarine fleet during World War II and in 1943, Doenitz became the commander of the German Navy. After Hitler's suicide, Doenitz was designated as successor and as such, commanded German forces for six days until surrendering to the Allies. Doenitz was found guilty of war crimes at the Nuremberg trials and served ten years in Spandau prison. Bibliography: Doenitz at Nuremberg : A Reappraisal . 1993. Inst Hist Review.