Frederick Augustus II, Grand Duke of Oldenburg
Frederick Augustus II was the last ruling Grand Duke of Oldenburg. He married Princess Elisabeth Anna of Prussia, daughter of Princess Maria Anna of Anhalt-Dessau and Prince Frederick Charles of Prussia. After her death, he married Elisabeth Alexandrine of Mecklenburg-Schwerin.
Reign
Frederick Augustus' reign began on 13 June 1900, when his father died. His reign came to an end on 11 November 1918, shortly before the German monarchy was abolished on 28 November 1918.Marriages and issue
On 18 February 1878, Frederick Augustus married Princess Elisabeth Anna of Prussia, a daughter of Prince Frederick Charles of Prussia. It was a double wedding, in which Princess Charlotte of Prussia married Bernhard, Hereditary Prince of Saxe-Meiningen on the same day as Elisabeth Anna in Berlin. The marriages were the first such occasions performed since Prussia had become the German Empire in 1870. Due to this increased status, the weddings were attended by many important personages, including King Leopold II of Belgium and his wife Queen Marie Henriette. The Prince of Wales also attended, as one of the brides was his niece.Frederick Augustus and Elisabeth Anna had two children:
| Name | Birth | Death | Notes |
| Duchess Sophia Charlotte | 2 February 1879 | 29 March 1964 | married Prince Eitel Friedrich of Prussia, a younger son of Wilhelm II of Germany. |
| Duchess Margaret | 13 October 1881 | 20 February 1882 | died in infancy. |
Elisabeth died on 28 August 1895, before he succeeded as Grand Duke. Before her death, her husband had been building a new residential palace; once she died, Frederick named the new building the Elisabeth-Anna-Palais in her honor.
On 24 October 1896, Frederick Augustus married Duchess Elisabeth Alexandrine of Mecklenburg-Schwerin, a daughter of Frederick Francis II, Grand Duke of Mecklenburg. He succeeded as Grand Duke of Oldenburg in 1900.
Frederick Augustus and Elisabeth had five children:
| Name | Birth | Death | Notes |
| Nicolas Frederick William, Hereditary Grand Duke of Oldenburg | 10 August 1897 | 3 April 1970 | married Princess Helena of Waldeck and Pyrmont. |
| Duke Frederick Augustus | 25 March 1900 | 26 March 1900 | twin with Alexandrine, died in infancy. |
| Duchess Alexandrine | 25 March 1900 | 26 March 1900 | twin with Frederick Augustus, died in infancy. |
| Duchess Ingeborg Alix | 20 July 1901 | 10 January 1996 | married Prince Stephan Alexander of Schaumburg-Lippe, a younger son of Georg, Prince of Schaumburg-Lippe and had Marie Alix among others. |
| Duchess Altburg Marie Mathilde Olga | 19 May 1903 | 16 June 2001 | married Josias, Hereditary Prince of Waldeck and Pyrmont. |
Frederick was forced to abdicate his throne at the end of World War I, when the former Grand Duchy of the German Empire joined the post-war German Republic. He and his family took up residence at Rastede Castle, where he took up farming and local industrial interests. A year after his abdication, he asked the Oldenburg Diet for a yearly allowance of 150,000 marks, stating that his financial condition was "extremely precarious".
In 1931, Frederick died in Rastede.