Wilhelm, German Crown Prince, Crown Prince of Prussia (Friedrich Wilhelm Victor August Ernst; 6 May 1882 – 20 July 1951) was the eldest child of the last Kaiser, Wilhelm II, German Emperor, and his consort Augusta Victoria of Schleswig-Holstein, and thus a great-grandson of Queen Victoria, and distant cousin to many British Royals, such as Queen Elizabeth II. As Emperor Wilhelm's heir, he was the last Crown Prince of the German Empire and the Kingdom of Prussia, until the abolition of the monarchy. Wilhelm became crown prince at the age of six in 1888, when his grandfather Frederick III died and his father became emperor. He was crown prince for 30 years until the fall of the empire on 9 November 1918. During World War I, he commanded the 5th Army from 1914 to 1916 and was commander of the Army Group German Crown Prince for the remainder of the war. After his return to Germany in 1923, he fought the Weimar Republic and campaigned for the reintroduction of the monarchy in Germany. After his plans to become president had been blocked by his father, Wilhelm supported Adolf Hitler's rise to power, but when Wilhelm realised that Hitler had no intention of restoring the monarchy, their relationship cooled. Wilhelm became head of the House of Hohenzollern on 4 June 1941 following the death of his father and held the position until his own death on 20 July 1951.