William I of Württemberg
On 24 January 1816, in Saint Petersburg, he married his first cousin, Grand Duchess Catherine Pavlovna of Russia (1788–1819), daughter of Emperor Paul I of Russia (1754–1801) and Princess Sophie Dorothea of Württemberg (1759–1828). The couple had two children:
Princess Dorothea of Courland
Dorothea was born on Friedrichsfelde Palace near Berlin, the fourth and last daughter of Duchess Dorothea of Courland, who was by then separated from her husband, Duke Peter of Courland. Dorothea's paternity is disputed but generally assigned to Count Aleksander Batowski, a Polish envoy to the Duchy of Courland. Her biological father was a close associate of her uncle Charles-Maurice de Talleyrand-Périgord during the Napoleonic period. Her three elder half sisters, all legitimate daughters of the Duke of Courland, were: Princess Wilhelmine, Duchess of Sagan; Princess Pauline, Duchess of Sagan; and Princess Johanna Katharina, Duchess of Acerenza. The Duke of Courland acknowledged her officially, which entitled her to be styled Princess of Courland. She was educated in Germany.
Looking for a wealthy heiress for his nephew Edmond, Talleyrand asked Tsar Alexander I of Russia to intervene with Dorothea's mother in favor of Edmond's marrying her. The marriage occurred on 21 and 22 April 1809 at Frankfurt amidst the Napoleonic Wars, presided over by Talleyrand's friend, Prince-Bishop Karl Theodor Anton Maria von Dalberg, and Dorothea thus became comtesse Edmond de Périgord and great-niece of then Count de Talleyrand-Périgord, prince of Bénévent. Educated in Germany, she was plunged into French society, where she represented the enemy. Her three sisters, also very anti-French, did not help her marriage and despite the birth of three children, the marriage became unhappy, with Edmond more concerned with gaming, war and other women than with his wife.