William, Duke of Nassau

On 9 January 1816, he succeeded his father, Duke Frederick William, as the Prince of Nassau-Weilburg and joint Duke of Nassau with his cousin, Frederick Augustus, of the Nassau-Usingen branch of his family. When his cousin and co-Duke died on 24 March 1816, Wilhelm inherited the Usingen territories and became sole ruler of the Duchy of Nassau. He kept the title of Duke of Nassau for the rest of his reign.

On 24 June 1813 in Weilburg, Wilhelm married his first wife, Princess Louise of Saxe-Altenburg (28 January 1794 Hildburghausen, Thüringen – 6 April 1825, Biebrich or Weilburg). She was a daughter of Frederick, Duke of Saxe-Altenburg (who, until 1826, had been the last Duke of Saxe-Hildburghausen) and his wife, Duchess Charlotte Georgine of Mecklenburg-Strelitz. They had eight children:

• Princess Auguste Luise Friederike Maximiliane Wilhelmine of Nassau-Weilburg (Weilburg, 12 April 1814 – Weilburg, 3 October 1814).
• Princess Therese Wilhelmine Friederike Isabelle Charlotte of Nassau-Weilburg (Weilburg, 17 April 1815 – Prague, 8 December 1871); married in Biebrich on 23 April 1837 Duke Peter of Oldenburg. Their grandson was the Imperial Russian General Grand Duke Nicholas Nikolaevich of Russia the Younger.
• Adolphe, Grand Duke of Luxembourg (24 July 1817 – 17 November 1905); the present Grand Ducal Family of Luxembourg, which became extinct in the male line in 1912, descends from him.
• Prince Wilhelm Karl Heinrich Friedrich of Nassau-Weilburg (Biebrich, 8 September 1819 – Biebrich, 22 April 1823).
• Prince Moritz Wilhelm August Karl Heinrich of Nassau-Weilburg (Biebrich, 21 November 1820 – Vienna, 23 March 1850), unmarried and without legitimate issue.
• Princess Marie Wilhelmine Luise Friederike Henriette of Nassau-Weilburg (Biebrich, 5 April 1822 – Biebrich, 3 April 1824).
• Prince Wilhelm Karl August Friedrich of Nassau-Weilburg (Biebrich, 12 August 1823 – Biebrich, 28 December 1828).
• Princess Marie Wilhelmine Friederike Elisabeth of Nassau-Weilburg (Biebrich, 29 January 1825 – Neuwied, 24 March 1902), married in Biebrich on 20 June 1842 Hermann, Prince of Wied (Neuwied, 22 May 1814 – Neuwied, 5 March 1864). Their daughter Elisabeth married King Carol I of Romania .

Wilhelm married, as his second wife, his first wife's niece, Princess Pauline of Württemberg (Stuttgart, 25 February 1810 – Wiesbaden, 7 July 1856) on 23 April 1829 in Stuttgart. Pauline was a daughter of Prince Paul of Württemberg and his wife Charlotte of Saxe-Hildburghausen.

Wilhelm and Pauline had four children:

• An unnamed daughter (Biebrich, 27 April 1830 – Biebrich, 28 April 1830).
• Princess Helene Wilhelmine Henriette Pauline Marianne of Nassau (Wiesbaden, 12 April 1831 – Bad Pyrmont, 27 October 1888), married in Wiesbaden on 26 September 1853 George Victor, Prince of Waldeck and Pyrmont and had issue. The Dutch royal family descends from this marriage through their daughter Emma who married King William III of the Netherlands.
• Prince Nikolaus Wilhelm of Nassau (20 September 1832 – 17 September 1905). Married, morganatically, Natalia Alexandrovna Pushkina, Countess of Merenberg. She was a daughter of Alexander Pushkin and his wife, Natalya Goncharova. They had issue, now extinct in male line.
• Princess Sophia Wilhelmine Marianne Henriette of Nassau (9 July 1836 – 30 December 1913). Married King Oscar II of Sweden. The present Belgian, Danish, Norwegian and Swedish royal families and the Luxembourg grand ducal family descend from this marriage.