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:
Anna Sophia of Prussia
She married on 24 February 1555 in Wismar to Duke John Albert I of Mecklenburg (1525-1576). As a wedding gift, her father mediated in a dispute between her husband and his brother Ulrich, Duke of Mecklenburg. On the occasion of his marriage, Duke John Albert I had the Fürstenhof Palace in Wismar remodeled in a Renaissance style. After the wedding, John Albert I and his bride moved into this palace.