The Siege of Bouchain (9 August – 12 September 1711), following the Passage of the Lines of Ne Plus Ultra (5 August 1711), was a siege of the War of the Spanish Succession, and the last major victory of John Churchill, 1st Duke of Marlborough. Marlborough broke through the French defensive lines and took Bouchain after a siege of 34 days. Its capture left Cambrai the only French-held fortress between the allied army and Paris.