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 Sophie of Sweden
On 25 July 1819 in Karlsruhe, Sophie married her half-grand-uncle Leopold I of Baden. They became the paternal grandparents of the Swedish Queen consort Victoria of Baden.