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:
Maria Feodorovna (Sophie Dorothea of Württemberg)
Although Paul and his wife were not as close as they once had been, there remained a good deal of warmth between them. Their relationship suffered further in the last years of Paul's life. After Maria gave birth to her tenth and last child in 1798, Paul became infatuated with nineteen-year-old Anna Lopukhina, and this time Paul assured his wife that his behavior was irreproachable and that the relationship was of a paternal nature.