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 Baden
Sophie was married to Woldemar, Prince of Lippe (1824–1895) second son of Leopold II, Prince of Lippe (1796–1851) and Princess Emilie of Schwarzburg-Sondershausen (1800–1867) on 9 November 1858 in Karlsruhe. The marriage was childless, leading to a dispute that lasted two decades between the two lines of the House of Lippe to inherit the principality after the death of Woldemar, in 1895.