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:
Sophia Dorothea of Hanover
Sophia Dorothea was born on 16 March 1687 (O.S.), in Hanover. She was the only daughter of George Louis of Hanover, later King George I of Great Britain, and his wife Sophia Dorothea of Celle. She was detested by her elder brother, King George II of Great Britain.