Kluck saw early service in the Franco-Prussian war, and moved steadily through the ranks, becoming in 1913, the inspector general of the Seventh Army District. In July, 1914, he was made commander of the First Army on the extreme right of the projected German offensive through Belgium, and captured Brussels on 20 August 1914. Although temporarily checked by the British at Mons, he continued his advance, outflanking General Smith-Dorrien's II Corps at Le Cateau on 26 August. At the request of General Karl von Bulow, he changed his axis of advance to move south and east of Paris, rather than the initially intended north and west which the Schlieffen Plan had projected. The change, though stunning in its attempt, allowed a successful Allied counter-attack at the Marne. Von Kluck, at the battle of the Ourcq, was nearly encircled by the Allies, but managed to extricate his forces and retreat. Nevertheless, von Kluck retained his command until badly wounded, he retired from active duty in October, 1916.