Henry, Prince of Prussia (1862–1929), the second son of Kaiser Frederick III and brother of Kaiser Wilhelm II, was a respected naval officer. One-time commander of the High Seas Fleet, he headed German naval forces in the Baltic during the war as a Grand Admiral. He also held the post of Inspector General of the Imperial Navy. He stepped down in February 1918 after the Bolsheviks had taken Russia out of the war.
His was a completely different personality than his brother, showing extraordinary tact in prewar visits to China and the United States. An outstanding seaman, Henry was a strong supporter of technology and innovation in the navy. He was revered by his officers and sailors but had a conflict with Admiral Tirpitz that kept him from being influential at the highest levels of wartime policy-making. After Kaiser Wilhelm's abdication, he continued to live in Germany and died there in 1929 of throat cancer, as had his father. Two of his sons carried hemophilia, inherited from their mother, Princess Irene of Hesse, a granddaughter of Queen Victoria.
Photo from the Pritzker Military Museum