| Date | Oldest | Youngest | Longest-Reigning |
| 1900 | Christian IX of Denmark (b. 1818) | Alfonso XIII of Spain (b. 1886) | Victoria of Great Britain (a. 1837) |
| 1901 | | | Franz Joseph of Austria (a. 1848) |
| 1906 | Franz Joseph of Austria (b. 1830) |
| 1912 | | Marie Adelaide of
Luxembourg (b. 1894)
|
| 1916 | Johannes II of Liechtenstein (b. 1840) | | Johannes II of Liechtenstein (a. 1858) |
| 1919 | | Charlotte of
Luxembourg (b. 1896) |
| 1927 | | Michael of Romania
(b. 1921) |
| 1929 | Franz of Liechtenstein (b. 1853) | | Alfonso XIII of Spain
(a. 1886) |
| 1930 | | Charlotte of
Luxembourg |
| 1931 | | | Wilhelmina of
Netherlands (a. 1890) |
| 1934 | | Peter II of
Yugoslavia (b. 1923) |
| 1938 | Gustaf V of Sweden
(b. 1858) |
| 1943 | | Simeon II of Bulgaria
(b. 1937) |
| 1946 | | Michael of Romania |
| 1947 | | Franz Josef II of
Liechtenstein (b. 1906) |
| 1948 | | | Haakon VII of
Norway (a. 1905) |
| 1949 | | Rainier III of Monaco
(b. 1923) |
| 1950 | Haakon VII of
Norway (b. 1872) |
| 1951 | | Baudouin I of Belgium
(b. 1930) |
| 1957 | Gustaf VI Adolf of Sweden (b. 1882) | | Charlotte of Luxembourg
(a. 1919) |
| 1964 | | Constantine II of
Greece (b. 1940) | Franz Joseph II of Liechtenstein (a. 1938) |
| 1973 | Olav V of Norway (b. 1903) | Carl XVI Gustaf of
Sweden (b. 1946) |
| 1989 | | | Rainier III of Monaco
(a. 1949) |
| 1991 | Jean of Luxembourg
(b. 1921) |
| 2000 | Rainier III of Monaco | Henri of Luxembourg
(b. 1955) |
| 2005 | Elizabeth II of Great Britain (b. 1926) | Albert II of Monaco (b. 1958) | Elizabeth II of Great Britain (a. 1952) |