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:
Sophia Dorothea of Celle
The desire for the marriage was almost purely financial, as Duchess Sophia wrote to her niece Elizabeth Charlotte, "One hundred thousand thalers a year is a goodly sum to pocket, without speaking of a pretty wife, who will find a match in my son George Louis, the most pigheaded, stubborn boy who ever lived, who has round his brains such a thick crust that I defy any man or woman ever to discover what is in them. He does not care much for the match itself, but one hundred thousand thalers a year have tempted him as they would have tempted anybody else".