Heinrich (Henry), Prince of Prussia (August 14, 1862, Potsdam – April 20, 1929, Hemmelmark [now belonging to Barkelsby]), German grand admiral. Heinrich was born in 1862 the second son of the future Kaiser Friedrich III. At the age of 15 he became the only Prussian prince to embark upon a military career in the Imperial Navy. After completing naval college Heinrich was promoted lieutenant commander in 1882. He was given his first command, a torpedo boat, in 1886. This was followed by a series sea-goi…