From August 1916, he commanded Army Group Rupprecht of Bavaria, which occupied the sector of the front opposite the British Expeditionary Force.

Rupprecht was born in Munich, the eldest of the thirteen children of Ludwig III, the last King of Bavaria, and of Archduchess Maria Theresa of Austria-Este, a niece of Duke Francis V of Modena.

In his youth, he spent much of his time at Schloss Leutstetten, Starnberg, and at the family's villa near Lindau, Lake Constance, where he was able to develop a keen interest in sports.

[2] Rupprecht's paternal grandfather, Luitpold, became de facto ruler of Bavaria when King Ludwig II and his successor Otto both were declared insane in 1886.

He rose to the rank of a colonel and became the commanding officer of the 2nd Infanterie Regiment Kronprinz but found enough opportunity to travel extensively to the Middle East, India, Japan and China.

While much of the German army participated in the Schlieffen plan, the Crown Prince led his troops in the Battle of Lorraine (14 to 25 August 1914).

[8] To the Kingdom of Prussia, Rupprecht suggested other areas of northern France, Walloon Belgium with Liege and Namur, and the salient of the Netherlands round Maastricht.

[4][10] Max Immelmann, one of the most famous German First World War flying aces, referred in a letter written on 25 June 1915 to a visit by Rupprecht to an airfield to inspect the new Fokker Eindecker aircraft.

[11] On 12 November 1918, in the wake of civil unrest in the last days of the war, Rupprecht's father, Ludwig III, promulgated the Anif declaration releasing his officials, officers and soldiers from their oaths.

Rupprecht escaped to Tyrol in fear of reprisals from the brief communist regime in Bavaria under Kurt Eisner but returned in September 1919.

Shortly after the 1922 Washington Naval Conference, he made a statement regarding the possible ban of aerial bombing, poison gas, sea blockades and long range guns, blaming them for a majority of civilian casualties during the last war.

He also advocated Germany's participation in future peace conferences, and he dismissed claims that Kaiser Wilhelm II was to blame for the First World War.

[13] Rupprecht was never enticed to join the Nazis in Germany, despite Hitler's attempts to win him over through Ernst Röhm and promises of royal restoration.

The Crown Prince in turn confessed to King George V at a lunch in London in the summer of 1934 that he considered Hitler to be insane.

[17] With the worsening of the Great Depression in 1932, a plan was floated to give Rupprecht dictatorial powers in Bavaria under the title of Staatskommissar.

Rupprecht was forced into exile in Italy in December 1939 (the last straw being the confiscation of Schloß Leutstetten by the Nazis) where he stayed as a guest of King Victor Emmanuel, residing mostly in Florence.

[2] In a memorandum in May 1943, he voiced his opinion that Germany would be completely defeated in the war and hoped to spare the German people from the worst when the Nazi regime finally fell.

Rupprecht continued to advocate the restoration of the Bavarian monarchy upon his return but found no support from the US occupation authorities who, however, treated him courteously.

General Dwight D. Eisenhower provided a special plane to fly him back to Munich in September 1945 and he returned to Schloß Leutstetten.