| Country | Sovereign | Born | Acceded | Consort (born) | Heir (born) |
 Principality of Liechtenstein |
 Prince Johann II |
5 Oct 1840 | 12 Nov 1858 |  Prince Franz (1853) |
|
 Kingdom of Spain |
 King Alfonso XIII |
17 May 1886 | 17 May 1886 |  Queen Victoria Eugenie (1887) |
 Infante Alfonso, Prince of Asturias (1907) |
 Kingdom of the Netherlands |
 Queen Wilhelmina |
31 Aug 1880 | 23 Nov 1890 |  Prince Hendrik (1876) |
 Princess Juliana (1909) |
 Kingdom of Italy |
 King Victor Emanuel III |
11 Nov 1869 | 29 Jul 1900 |  Queen Helena (1873) |
 Crown Prince Umberto (1904) |
 Kingdom of Norway |
 King Haakon VII |
3 Aug 1872 | 18 Nov 1905 |  Queen Maud (1869) |
 Crown Prince Olav (1903) |
 Kingdom of Sweden |
 King Gustaf V |
16 Jun 1858 | 8 Dec 1907 |  Queen Victoria (1862) |
 Crown Prince Gustaf Adolf (1882) |
 Kingdom of Belgium |
 King Albert I |
8 Apr 1875 | 23 Dec 1909 |  Queen Elisabeth (1876) |
 Prince Leopold, Duke of Brabant (1901) |
 United Kingdom of Great Britain and Ireland Irish Free State |
 King George V |
3 Jun 1865 | 6 May 1910 |  Queen Mary (1867) |
 Prince Edward, Prince of Wales (1894) |
 Kingdom of Denmark  Kingdom of Iceland (1 Dec 1918) |
 King Christian X |
26 Sep 1870 | 14 May 1912 |  Queen Alexandrine (1879) |
 Crown Prince Frederik (1899) |
 Kingdom of Romania |
 King Ferdinand I |
24 Aug 1865 | 10 Oct 1914 |  Queen Marie (1875) |
 Crown Prince Carol (1893) |
 Kingdom of Bulgaria |
 King Boris III |
30 Jan 1894 | 3 Oct 1918 |  Kyril, Prince of Preslav (1895) |
|
 Grand Duchy of Luxembourg |
 Grand Duchess Charlotte |
23 Jan 1896 | 14 Jan 1919 |  Prince Felix (1893) |
Her. Grand Duke Jean (1921) |
 Kingdom of Hungary (29 Feb 1920) |
(Admiral Miklós Horthy, Regent) |
(18 Jun 1868) | (1 Mar 1920) | ||
 Kingdom of Serbs, Croats, & Slovenes (1 Dec 1918) |
 King Alexander I |
16 Dec 1888 | 16 Aug 1921 |  Queen Marie (1900) |
 Crown Prince Peter (1923) |
 Principality of Monaco |
 Prince Louis II |
12 Jul 1870 | 26 Jun 1922 |  Princess Charlotte (1898) |