through diplomatic interventions, though separating the two did not happen until the autumn of 1804. During his time in Paris, Frederick William received financial support from the Landstände and later from Napoleon. Heir to the throne On 11 September 1805 Frederick William left Paris and returned (after a visit to his grandparents, the Duke and Duchess of Brunswick-Wolfenbüttel in Brunswick) to Stuttgart, where in November he met his father for the first time in a few years. His return was mainly due to the change in the political climate. The United Kingdom, which had been at war with Napoleon since 1803, formed an alliance with Russia and Austria. Napoleon had Württemberg's neighbours of Baden and Bavaria on his side, so Württemberg was forced, after some hesitation, to yield to French pressure and also enter into an alliance with Napoleon. The French Foreign Minister Talleyrand suggested a coup against Elector Frederick, in which his son was to replace him, but Frederick William opposed the suggestion. This act is regarded as the main reason for William's subsequent aversion to Napoleon. Friedrich refused to involve his son in the affairs of state, but gave him his own court headed by his friend, Ernst von Pfuel-Riepurr, who had accompanied him in his time out of the country. Frederick William took the time to further his education, including acquiring a knowledge of agriculture. From 1 January 1806, the territorial gains as a result of the German mediatization enlarged the electorate of Württemberg and it became a kingdom. In 1806, Prussia joined the coalition against Napoleon and was defeated and occupied within a few weeks. Napoleon wanted Württemberg to be bound to him closer by marriage. On 13 August 1807 Frederick William's sister, Catherine, married Napoleon's brother Jérôme, the king of the newly created Kingdom of Westphalia. In order to prevent Napoleon arranging a marriage for him, Frederick William sought permission from his father to marry Charlotte (later Caroline) Augusta, the daughter of the Bavarian king Maximilian I Joseph. After lengthy negotiations took place, the pair were married on 8 June 1808 in Munich. Since it was purely a marriage of convenience and Frederick William had no interest in a deeper relationship with his wife, Charlotte became increasingly lonely in Stuttgart. Frederick often stayed in Kassel at the court of his brother-in-law, Jérôme. Here he met Jérôme's former lover, Blanche La Flèche, Baroness of Keudelstein. He