After the treaty of Tilsit (7 July 1807) Savary proceeded to St Petersburg as the French ambassador, but was soon replaced by General Caulaincourt, another accessory to the execution of the duc d'Enghien. The repugnance of the empress dowager to Savary is said to have been one of the reasons of his recall, but it is more probable that Napoleon felt the need of his gifts for intrigue in the Spanish affairs which he undertook at the close of 1807. With the title of duke of Rovigo (a small town in Venetia), Savary set out for Madrid when Napoleon's plans for gaining the mastery of Spain were nearing completion. With Murat Savary made skilful use of the schisms in the Spanish royal family (March–April 1808), and persuaded Charles IV of Spain, who had recently abdicated under duress, and his son Ferdinand VII, the de facto king of Spain, to refer their claims to Napoleon. Savary induced Ferdinand to cross the Pyrenees and proceed to Bayonne—a step which cost him his crown and his liberty until 1814.
