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:
Paul of Greece
On 9 January 1938, Paul married Princess Frederica of Hanover, his first cousin once removed through Frederick III, German Emperor, and Victoria, Princess Royal, and second cousin through Christian IX of Denmark, at Athens. They had three children:During most of World War II, from 1941 to 1946, when Greece was under German occupation, Paul was with the Greek government-in-exile in London and Cairo. From Cairo, he broadcast messages to the Greek people.