Biography. He joined the army in 1934 (infantry regiment 8 in Frankfurt/Oder) and participated in the Invasion of Poland in 1939. One year later he was dismissed from the army by Hitler's Prinzenerlaß, following the death of his elder brother Prince Wilhelm of Prussia, who was wounded in France on 23 May 1940 and died in a Field hospital in Belgium three days later.
Prince Adalbert was born on 14 July 1884 as the third son of the then Prince Wilhelm of Prussia and his first wife, Princess Augusta Victoria of Schleswig-Holstein. He was born in the Marmorpalais of Potsdam in the Province of Brandenburg , where his parents resided until his father acceded to the throne as Emperor Wilhelm II in 1888.