| REFERENCE | TITLE | NAME | BORN | DIED | TITLE | NAME | BORN | DIED | COMMENTS | |
| 31 | Duke | Peter I of Oldenburg | 1755 | 1829 | Duchess | Friederike of Württemberg | 1765 | 1785 | See 22.7 - Peter succeeded his cousin Wilhelm (1754 - 1823) as Duke of Oldenburg. Wilhelm's father Friedrich August (1711-1785) was Duke of Holstein-Gottorp and was ceded Oldenburg on 14 December 1773 by his cousin Paul (later Emperor Paul I of all the Russias). Oldenburg was elevated from a County to a Duchy in 29 December 1774 (publicly announced on 22 March 1777) with further elevation to a Grand Duchy on 9 June 1815. However the title of Grand Duke was not used until the accession of Duke Peter's son August in 1829 | |
| 31.1 | Grand Duke | August of Oldenburg | 1783 | 1853 | Princess | Adelheid of Anhalt-Bernburg-Schaumburg-Hoym | 1800 | 1820 | Adelheid and Ida were sisters | |
| 31.1 | Grand Duke | August of Oldenburg | 1783 | 1853 | Princess | Ida of Anhalt-Bernburg-Schaumburg-Hoym | 1804 | 1828 | Adelheid and Ida were sisters | |
| 31.1 | Grand Duke | August of Oldenburg | 1783 | 1853 | Princess | Cecilie of Sweden | 1807 | 1844 | See 32.145 | |
| 31.11 | Duchess | Amelie of Oldenburg | 1818 | 1875 | Prince | Otto of Bavaria | 1815 | 1867 | See 18.13 - Otto became King of Greece in 1832 and fled the country in 1862 after an insurrection. He was succeeded as King by Prince Wilhelm of Denmark | |
| 31.12 | Duchess | Friederike of Oldenburg | 1820 | 1891 | Baron | Maximilian von Washington | 1829 | 1903 | A Genealogy containing Maximilian von Washington can be found here | |
| 31.13 | Grand Duke | Peter II of Oldenburg | 1827 | 1900 | Princess | Elisabeth of Saxe-Altenburg | 1826 | 1896 | See 30.44 | |
| 31.131 | Grand Duke | Friedrich August of Oldenburg | 1852 | 1931 | Princess | Elisabeth of Prussia | 1857 | 1895 | See 11.512 - Friedrich abdicated his throne on 11 November 1918. | |
| 31.131 | Grand Duke | Friedrich August of Oldenburg | 1852 | 1931 | Duchess | Elisabeth Alexandrine of Mecklenburg-Schwerin | 1869 | 1955 | See 23.118 - Friedrich abdicated his throne on 11 November 1918 | |
| 31.1311 | Duchess | Sophie Charlotte of Oldenburg | 1879 | 1964 | Prince | Eitel-Friedrich of Prussia | 1883 | 1942 | See 11.2112 | |
| 31.1311 | Duchess | Sophie Charlotte of Oldenburg | 1879 | 1964 | Harald von Hedemann | 1887 | 1951 | |||
| 31.1312 | Duchess | Margarete of Oldenburg | 1881 | 1882 | ||||||
| 31.1313 | Hereditary Grand Duke | Nikolaus of Oldenburg | 1897 | 1970 | Princess | Helene of Waldeck and Pyrmont | 1899 | 1948 | See 42.63 | |
| 31.1313 | Hereditary Grand Duke | Nikolaus of Oldenburg | 1897 | 1970 | Anne-Marie von Schutzbar gen. Milchling | 1903 | 1991 | |||
| 31.13131 | Duke | Anton Günther of Oldenburg | 1923 | Princess | Amelia of Löwenstein-Wertheim-Freudenberg | 1923 | Anton Günther is the present Head of the Ducal House of Oldenburg | |||
| 31.131311 | Duchess | Helene Elisabeth of Oldenburg | 1953 | |||||||
| 31.131312 | Duke | Christian Nikolaus of Oldenburg | 1955 | Countess | Caroline zu Rantzau | 1962 | The ancestry of Countess Caroline zu Rantzau | |||
| 31.1313121 | Duke | Alexander Paul of Oldenburg | 1990 | |||||||
| 31.1313122 | Duke | Philipp Konstantin of Oldenburg | 1991 | |||||||
| 31.1313123 | Duke | Anton Friedrich of Oldenburg | 1993 | |||||||
| 31.1313124 | Duchess | Katharina Bibiane of Oldenburg | 1997 | |||||||
| 31.13132 | Duchess | Rixa of Oldenburg | 1924 | 1939 | Rixa died in a riding accident, when her horse had a heart failure | |||||
| 31.13133 | Duke | Peter Friedrich of Oldenburg | 1926 | Princess | Gertrud of Löwenstein-Wertheim-Freudenberg | 1926 | ||||
| 31.131331 | Duke | Friedrich August of Oldenburg | 1952 | Belinda Tatham Warter | 1954 | |||||
| 31.1313311 | Duchess | Anastasia of Oldenburg | 1982 | |||||||
| 31.1313312 | Duchess | Alice of Oldenburg | 1986 | |||||||
| 31.1313313 | Duchess | Cara of Oldenburg | 1993 | |||||||
| 31.131332 | Duchess | Margarete of Oldenburg | 1954 | Prince | Philipp von Croÿ | 1957 | ||||
| 31.1313321 | Prince | Alexander Friedrich-August von Croÿ | 1987 | |||||||
| 31.1313322 | Prince | Maximilian Johannes von Croÿ | 1988 | |||||||
| 31.1313323 | Princess | Rosalie Franziska von Croÿ | 1990 | |||||||
| 31.131333 | Duke | Nikolaus of Oldenburg | 1955 | Anna Dyckerhoff | 1958 | |||||
| 31.1313331 | Duke | Christoph of Oldenburg | 1985 | |||||||
| 31.1313332 | Duke | Georg of Oldenburg | 1990 | |||||||
| 31.1313333 | Duke | Oscar of Oldenburg | 1991 | |||||||
| 31.131334 | Duke | Georg-Moritz of Oldenburg | 1957 | |||||||
| 31.13134 | Duchess | Eilika of Oldenburg | 1928 | Prince | Emich of Leiningen (7th Prince of Leiningen) | 1926 | 1991 | See 39.21231 | ||
| 31.13135 | Duke | Egilmar of Oldenburg | 1934 | |||||||
| 31.13136 | Duke | Friedrich August of Oldenburg | 1936 | Princess | Marie Cecile of Prussia | 1942 | See 11.211123 | |||
| 31.13136 | Duke | Friedrich August of Oldenburg | 1936 | Countess | Donata of Castell-Rüdenhausen | 1950 | Donata was previously married to Prince Louis Ferdinand of Prussia who's a brother of Princess Marie-Cecilie (Duke Friedrich August's first wife) | |||
| 31.131361 - QVD | Duke | Paul-Wladimir of Oldenburg | 1969 | Maria del Pilar Méndez de Vigo y Löwenstein-Wertheim-Rosenberg | 1970 | Maria is the daughter of Princess Monika of Löwenstein-Wertheim-Rosenberg (sister of Prince Alois-Konstantin of Löwenstein-Wertheim-Rosenberg) and Jaime Méndez de Vigo y del Arco | ||||
| 31.1313611 - QVD | Duke | Kirill Friedrich-August of Oldenburg | 2002 | |||||||
| 31.1313612 - QVD | Duke | Carlos Jakobus of Oldenburg | 2004 | |||||||
| 31.1313613 - QVD | Duke | Paul Marie of Oldenburg | 2005 | |||||||
| 31.1313614 - QVD | Duchess | Maria Assunta of Oldenburg | 2007 | |||||||
| 31.131362 - QVD | Duchess | Rixa of Oldenburg | 1970 | |||||||
| 31.131363 - QVD | Duchess | Bibiane of Oldenburg | 1974 | Peter Dorner | 1972 | |||||
| 31.13137 | Duchess | Altburg of Oldenburg | 1938 | Baron | Rudiger von Erffa | 1936 | ||||
| 31.13138 | Duke | Huno of Oldenburg | 1940 | Countess | Felictitas-Anita Schwerin von Krosigk | 1941 | Duke Huno & Duke Johann are twins | |||
| 31.131381 | Duchess | Beatrix Amelie of Oldenburg | 1971 | |||||||
| 31.131382 | Duchess | Sophie Altburg of Oldenburg | 1972 | Joseph-Maria von Radowitz | 1969 | |||||
| 31.13139 | Duke | Johann of Oldenburg | 1940 | Countess | Ilka of Ortenburg | 1942 | Duke Huno & Duke Johann are twins | |||
| 31.131391 | Duchess | Eilika of Oldenburg | 1972 | Archduke | Paul Georg of Austria | 1964 | See 19.J32117 | |||
| 31.131392 | Duchess | Tatjana Ingeborg of Oldenburg | 1974 | |||||||
| 31.131393 | Duke | Konstantin Nikolaus of Oldenburg | 1975 | |||||||
| 31.1314 | Duke | Friedrich August of Oldenburg | 1900 | 1900 | ||||||
| 31.1315 | Duchess | Alexandrine of Oldenburg | 1900 | 1900 | ||||||
| 31.1316 | Duchess | Ingeborg Alix of Oldenburg | 1901 | 1996 | Prince | Stephan of Schaumburg-Lippe | 1891 | 1965 | See 43.125 | |
| 31.1317 | Duchess | Altburg of Oldenburg | 1903 | 2001 | Prince | Josias of Waldeck and Pyrmont | 1896 | 1967 | See 42.61 - Prince Josias held high command in Hitler's Nazi and at the end of the second World War he was arrested and tried for war crimes. In 1947 he was sentenced to life imprisonment, which was later commuted to 20 years although he was released in 1950 on health grounds. | |
| 31.132 | Duke | George of Oldenburg | 1855 | 1939 | ||||||
| 31.14 | Duke | Alexander of Oldenburg | 1834 | 1835 | ||||||
| 31.15 | Duke | August of Oldenburg | 1836 | 1837 | ||||||
| 31.16 | Duke | Elimar of Oldenburg | 1844 | 1895 | Baroness | Natalie Vogel von Friesenhof | 1854 | 1937 | Baroness Natalie was created Countess von Welsburg on 25 April 1896 | |
| 31.2 | Duke | George of Oldenburg | 1784 | 1812 | Grand Duchess | Catherine of Russia | 1788 | 1819 | See 4.6 - Catherine was married secondly to King Wilhelm I of Württemberg | |
| 31.21 | Duke | Alexander of Oldenburg | 1810 | 1829 | ||||||
| 31.22 | Duke | Peter of Oldenburg | 1812 | 1881 | Princess | Therese of Nassau-Weiburg | 1815 | 1871 | See 33.2 | |
| 31.221 | Duchess | Alexandra of Oldenburg | 1838 | 1900 | Grand Duke | Nicholas of Russia | 1831 | 1891 | See 4.97 - Alexandra took the name "Alexandra Petrovna" on her marriage | |
| 31.222 | Duke | Nikolaus of Oldenburg | 1840 | 1886 | Marie Bulatzelly | 1845 | 1907 | Marie was created Countess von Osternburg on 13 July 1863 | ||
| 31.223 | Duchess | Cecilie of Oldenburg | 1842 | 1843 | ||||||
| 31.224 | Duke | Alexander of Oldenburg | 1844 | 1932 | Princess | Eugenia Romanovsky | 1845 | 1925 | See 18.274 | |
| 31.2241 | Duke | Peter of Oldenburg | 1868 | 1924 | Grand Duchess | Olga of Russia | 1882 | 1960 | See 4.9136 - Some sources refer to Olga as the last Grand Duchess of Russia. However, this does not take into account whether Marie (1953 - ) daughter of Grand Duke Vladimir is entitled to use the style of Grand Duchess of Russia | |
| 31.2241 | Duke | Peter of Oldenburg | 1868 | 1924 | Olga Ratova-Rognova | 1878 | 1953 | |||
| 31.225 | Duchess | Katharine of Oldenburg | 1846 | 1866 | ||||||
| 31.226 | Duke | Georg of Oldenburg | 1848 | 1871 | ||||||
| 31.227 | Duke | Konstantin of Oldenburg | 1850 | 1906 | Aggripina Djaparidze | 1855 | 1926 | Aggripina was created Countess von Zarnekau on 20 October 1882 | ||
| 31.2271 | Countess | Alexandra von Zarnekau | 1883 | 1957 | Prince | George Yurievsky | 1872 | 1913 | See 4.919 | |
| 31.2271 | Countess | Alexandra von Zarnekau | 1883 | 1957 | Leo Narishkin | 1876 | 1931 | |||
| 31.228 | Duchess | Therese Friederike of Oldenburg | 1852 | 1883 | Duke | George of Leuchtenberg | 1852 | 1912 | See 18.277 |