After winning fame as a submarine expert, he commanded the High Seas Fleet during World War I (1916–18). His hopes of dividing and defeating the British Grand Fleet at Jutland (1916) failed, but his brilliant manoeuvring saved his own fleet. In October 1918 the German fleet at Kiel mutinied under him, refusing to put out to sea. The mutiny spread rapidly to north-west Germany, and by November Germany had accepted an end to World War I.