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 of Hanover ( – 28 June 1757) was a Queen consort in Prussia as spouse of Frederick William I. She was the sister of George II, King of Great Britain and the mother of Frederick II, King of Prussia.