Karl Ludwig August Pfühl was born in 1757 into Württemberg nobility and entered the Württemberg army in 1774 before subsequently joining the Prussian army in 1777. By 1781, he was a member of the general staff under Frederick the Great and in 1793, he participated in the Rhine campaign as part of the First Coalition against France. He was promoted to chief of staff to Frederick William III of Prussia, but left after the defeat of 1806 and entered the service of Alexander I of Russia, beginning his role at the turn of the year 1806-1807 with the rank of major general. He proved popular with the Tsar and proceeded to instruct him on the art of war, preparing a defence plan should hostilities break out between Russia and France. He was promoted to lieutenant general on 11 September, 1809, and was attached to Russian headquarters in 1810 and 1811. Anticipating a war of attrition, Pfühl advocated an entirely defensive plan, with Russian forces withdrawing to Drissa, a fortified camp on the Dvina (near Polotsk, in Belarus), and harrying the invading force from the wings and from behind. After Napoleon's invasion and march on Moscow, the plan was considered too dangerous by his fellow officers, and the Russian army retired deeper into Russia following advice from Barclay de Tolly. Although Pfühl remained in Russia for the remainder of the campaign, he was to have no further role in military decisions. Nevertheless, Alexander is recorded as having declared to Pfühl on 12 December, 1813, following Napoleon's retreat, "It is you who conceived of the plan that - with collusion of Providence - has resulted in Russia and Europe's salvation". He remained unpopular with the Russian officers on Alexander's staff and in 1813 he became military advisor to Prince Frederick of the Netherlands in The Hague. In 1814, he was made Russian ambassador to the Netherlands. After the mental breakdown of his wife in 1821, they were separated and he resigned his post and retired to Stuttgart, where he died on 25 April, 1826.