turn to garrison duty he set to work so zealously to remedy the
defects in his education caused by his father's poverty, that in 1801 he
was admitted to the Berlin Academy for young officers, then directed by
Scharnhorst. Scharnhorst, attracted by his pupil's industry and force of
character, paid special attention to his training, and profoundly
influenced the development of his mind. In 1803, on Scharnhorst's
recommendation, Clausewitz was made "adjutant" (aide-de-camp) to Prince
August, and he served in this capacity in the campaign of Jena (1806),
being captured along with the prince by the French at Prenzlau. A
prisoner in France and Switzerland for the next two years, he returned
to Prussia in 1809; and for the next three years, as a departmental
chief in the ministry of war, as a teacher in the military school, and
as military instructor to the crown prince, he assisted Scharnhorst in
the famous reorganization of the Prussian army. In 1810 he married the
countess Marie von Bruehl.

On the outbreak of the Russian war in 1812, Clausewitz, like many other
Prussian officers, took service with his country's nominal enemy. This
step he justified in a memorial, published for the first time in the
_Leben Gneisenaus_ by Pertz (Berlin, 1869). At first adjutant to General
Phull, who had himself been a Prussian officer, he served later under
Pahlen at Witepsk and Smolensk, and from the final Russian position at
Kaluga he was sent to the army of Wittgenstein. It was Clausewitz who
negotiated the convention of Tauroggen, which separated the cause of
Yorck's Prussians from that of the French, and began the War of
Liberation (see YORCK VON WARTENBURG; also Blumenthal's _Die Konvention
von Tauroggen_, Berlin, 1901). As a Russian officer he superintended the
formation of the _Landwehr_ of east Prussia (see STEIN, BARON VOM), and
in the campaign of 1813 served as chief of staff to Count Wallmoden. He
conducted the fight at Goehrde, and after the armistice, with Gneisenau's
permission, published an account of the campaign (_Der Feldzug von 1813
bis zum Waffenstillstand_, Leipzig, 1813). This work was long attributed
to Gneisenau himself. After the peace of 1814 Clausewitz re-entered the
Prussian service, and in the Waterloo campaign was present at Ligny and
Wavre as General Thielmann's chief of staff. This post he retained till
1818, when he was promoted major-general and appointed director of the
_Allgemeine Kriegsschule_. Here he re