Karl Dönitz was a German admiral and played an important role in World War II. Starting his career in the Imperial German Navy, Dönitz went on to play an instrumental role in the naval history of the Second World War. He became a war prisoner in 1918 when submarine UB-68 under his command was sunk by the British forces. During the imprisonment, he devised a submarine warfare strategy, Rudeltaktik. Although submarine construction by Germany was banned according to ‘Treaty of Versailles’ Dönitz secretly supervised construction of U-boat fleet and became its commander in 1936. He became senior submarine officer in Kriegsmarine at the outset of the Second World War and was elevated as Grand Admiral or Großadmiral in January 1943. In April 1945, he was appointed by Hitler as head of the northern military and civil command and later as per Hitler’s last political testament, Dönitz became head of state of Germany. After Allied powers dissolved Flensburg Government headed by Dönitz, he was convicted at the Nuremberg trials and sentenced to 10 years imprisonment. Following his release, he lived in a village for the rest of his life.