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:
Prince Paul of Württemberg
Shortly before his marriage, Paul had a mistress, an actress named Friederike Margrethe Porth (22 August 1776, Halberstadt - 9 June 1860, Frankfurt am Main). Friederike was the daughter of Johann Carl Porth (1748, Barchwitz, Silesia - 18 June 1794, Weimar) and his wife Caroline (c. 1752 - died after 1797, Weimar).