| Country | Sovereign | Born | Acceded | ||
| Austria-Hungary | Emperor Franz Joseph I | 18 August | 1830 | 2 December | 1848 |
| Liechtenstein | Prince Johann II | 5 October | 1840 | 12 November | 1858 |
| Montenegro | King Nikola I | 7 October | 1841 | 13 August | 1860 |
| Romania | King Carol I | 20 April | 1839 | 20 April | 1866 |
| Spain | King Alfonso XIII | 17 May | 1886 | 17 May | 1886 |
| Bulgaria | King Ferdinand I | 26 February | 1861 | 7 July | 1887 |
| Germany | Emperor Wilhelm II | 27 January | 1859 | 15 June | 1888 |
| Monaco | Prince Albert | 13 November | 1848 | 10 September | 1889 |
| Netherlands | Queen Wilhelmina | 31 August | 1880 | 23 November | 1890 |
| Russia | Emperor Nicholas II | 18 May | 1868 | 1 November | 1894 |
| Italy | King Vittorio Emanuele III | 11 November | 1869 | 29 July | 1900 |
| Serbia | King Peter I | 11 July | 1844 | 12 June | 1903 |
| Norway | King Haakon VII | 3 Aug | 1872 | 18 November | 1905 |
| Sweden | King Gustaf V | 16 June | 1858 | 8 December | 1907 |
| Ottoman Empire | Sultan Mehmed V | 2/3 November | 1844 | 27 April | 1909 |
| Belgium | King Albert I | 8 April | 1875 | 23 December | 1909 |
| United Kingdom | King George V | 3 June | 1865 | 6 May | 1910 |
| Luxembourg | Grand Duchess Marie Adelaide | 14 June | 1894 | 25 February | 1912 |
| Denmark | King Christian X | 26 September | 1870 | 14 May | 1912 |
| Greece | King Constantine I | 2 August | 1868 | 18 March | 1913 |
| State | Ruler | Born | Acceded | ||
| Saxe-Meiningen | Duke Georg II | 2 Apr | 1826 | 20 Sep | 1866 |
| Bavaria | King Otto I | 27 Apr | 1848 | 13 Jun | 1886 |
| German Empire (Prussia) | Emperor (King) Wilhelm II | 27 Jan | 1859 | 15 Jun | 1888 |
| Württemberg | King Wilhelm II | 25 Feb | 1848 | 6 Oct | 1891 |
| Hesse | Grand Duke Ernst Ludwig | 25 Nov | 1868 | 13 Mar | 1892 |
| Waldeck & Pyrmont | Prince Friedrich | 20 Jan | 1865 | 12 May | 1893 |
| Mecklenburg-Schwerin | Grand Duke Friedrich Franz IV | 9 Apr | 1882 | 10 Apr | 1897 |
| Oldenburg | Grand Duke Friedrich August II | 16 Nov | 1852 | 13 Jun | 1900 |
| Saxe-Coburg & Gotha | Duke Carl Eduard | 19 Jul | 1884 | 30 Jul | 1900 |
| Saxe-Weimar-Eisenach | Grand Duke Wilhelm Ernst | 10 Jun | 1876 | 5 Jan | 1901 |
| Reuss (Senior Line) | Prince Heinrich XXIV | 20 Mar | 1878 | 19 Apr | 1902 |
| Anhalt | Duke Friedrich II | 19 Aug | 1856 | 24 Jan | 1904 |
| Mecklenburg-Strelitz | Grand Duke Adolf Friedrich V | 22 Jul | 1848 | 30 May | 1904 |
| Saxony | King Friedrich August III | 25 May | 1865 | 15 Oct | 1904 |
| Lippe | Prince Leopold IV | 30 May | 1871 | 13 Jan | 1905 |
| Baden | Grand Duke Friedrich II | 9 Jul | 1857 | 28 Sep | 1907 |
| Saxe-Altenburg | Duke Ernst II | 31 Aug | 1871 | 7 Feb | 1908 |
| Schwarzburg | Prince Günther | 21 Aug | 1852 | 28 Mar | 1909 |
| Schaumburg-Lippe | Prince Adolf II | 23 Feb | 1883 | 29 Apr | 1911 |
| Reuss (Junior Line) | Prince Heinrich XXVII | 10 Nov | 1858 | 29 Mar | 1913 |
(By May 1913, the Balkan League of Greece, Servia, & Bulgaria had already mostly expelled the Ottoman Empire from Europe, but borders were not entirely settled yet and most maps in use would have still looked like this.)