He was sent to negotiate the marriage of Charlotte Bonaparte to the King Ferdinand VII, which was rejected by Napoleon.

[1] He then became part of a delegation, along with the Dukes of Frías and Medinaceli, that received Napoleon in Bayonne.

After the King left Madrid in July 1808, he joined the War of Independence and was declared a traitor along with several other Dukes by Napoleon.

[1] He married María Vicenta Solís Vignancourt Lasso de la Vega, 6th Duchess of Montellano, 4th Duchess of Arco, 12th Marquise of Miranda de Anta and 7th Countess of Saldueña (c. 1780 – 4 June 1840) on 29 October 1798.

Their marriage was unhappy and they had two children: He died in Paris on 27 November 1822, at the age of 43 due to a horse fall.