Alcántara held the following titles: the 13th Duke of the Infantado, 9th Duke of Pastrana, 9th Duke of Estremera, 10th Duke of Francavilla, plus others. He was an extremely rich, powerful and popular figure in Spain generally and in court circles. He was "more educated than most of the Spanish grandees", having been raised and schooled in Paris. When Spain declared war on Revolutionary France in 1793, he raised an infantry regiment at his own expense. He fought with it in Catalonia against the French beside a Portuguese division and commanded a brigade of the 2nd division of the Army of Estremadura. After the Treaty of Amiens, he used the peace to establish cotton mills in Catalonia using technical experts from England. He was interested in science generally and in 1802 he ordered the first 'double chronometer' from Abraham-Louis Breguet, the world's foremost watchmaker. In the following years he became very close to Prince Ferdinand, the heir to the Spanish throne. This led him into conflict with the weak King Charles IV and his ambitious chief minister Godoy. Infantado was banished from Madrid in 1805. Within two years, and unfortunately for the duke's quiet life, Ferdinand was arrested and amongst his papers was found a nomination for the duke to be Commander-in-Chief of the Spanish forces. Tried and sentenced to death as a traitor, he was reprieved by popular sentiment and the intervention of the French Ambassador. A revolt in March 1808 resulted in the abdication of the king, the sacking of his manipulative chief minister Godoy and the ascent of Ferdinand VII to the Spanish throne, with the Duke of Infantado at his side. Taking advantage of the chaos, Napoleon "invited" the factions including the Duke, to a conference in Bayonne. At this meeting a new Spanish constitution was signed by the assembled Spanish deputies that resulted in the throne passing to Joseph Bonaparte, Napoleon's brother. The only major Spanish figure that spoke in opposition was the Duke of Infantado, who "had opposed to the utmost any recognition of the foreign monarch". Not long afterwards the duke called the nation to arms to resist the French, for which he was condemned as a traitor yet again, but this time by Napoleon. At the head of the Spanish army he was defeated by the French in 1809 at the Battle of Uclés. His palace at Guadalajara and all his goods were confiscated by Joseph. The duke joined forces with the British, at that time under Sir John Moore. He was extremely highly regarded by the British plenipotentiary, John Hookham Frere, who was accustomed to late and inaccurate intelligence from his allies: "Had Sir John Moore been so fortunate as to find so candid a correspondent as the Duke of Infantado, a person who would describe things as they were, there is no doubt that the events and conclusion of the campaign would have been very different", referring to Moore's retreat to Corunna. Wellington later had much cordial correspondence with the duke during the later stages of the Peninsular War. Amusingly, but quite naturally for the times, all the correspondence between these allies during the war with France was in French. In 1811 the Spanish parliament, the Cortes, nominated him as the President of the Council of Spain and sent him on a secret mission to the Prince Regent in London. He returned in 1812 and although he was proposed by Wellington as head of the 4th Army under British control, his enemies at the Spanish court decreed otherwise and he had to be content with leading his own regiment. After the end of the war with France in 1814 he retired again. He was recalled in 1823 to the Presidency of the Regency and was responsible for returning the king to the throne. Soon afterwards, tired of intrigue in the court and government, he retired to his country estates and eventually died there in 1841. He never married, but had one illegitimate son and two illegitimate daughters. His titles were divided amongst his son Manuel, and his nephew Pedro de Alcántara Tellez Girón y Beaufort, who became 14th Duke of the Infantado.
