Archduke Charles Stephen Eugene Viktor Felix Maria of Austria was a member of the House of Habsburg, a Grand Admiral in the Austro-Hungarian Navy and candidate for the Polish crown.

The Kingdom of Poland, also known informally as the Regency Kingdom of Poland, was a short-lived polity that was proclaimed during World War I by the German Empire and Austria-Hungary on 5 November 1916 on the territories of formerly Russian-ruled Congress Poland held by the Central Powers as the Government General of Warsaw and which became active on 14 January 1917. It was subsequently transformed between 7 October 1918 and 22 November 1918 into the independent Second Polish Republic, the customary ceremonial founding date of the latter being later set at 11 November 1918.