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:
Grand Duchess Olga Pavlovna of Russia
Grand Duchess Olga Pavlovna of Russia (; ) was a "Grand Duchess of Russia" as the second youngest daughter and seventh child of Emperor Paul I of Russia and his empress consort, Sophie Dorothea of Württemberg.