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 Hohenberg
Princess Sophie of Hohenberg ("Sophie Marie Franziska Antonia Ignatia Alberta von Hohenberg"; – ) was the only daughter of Archduke Franz Ferdinand of Austria and his morganatic wife Sophie, Duchess of Hohenberg, both of whom were assassinated at Sarajevo on 28 June 1914. Their assassination triggered the First World War, thus Sophie and her two brothers are sometimes described as the first orphans of the First World War.