The Germans initiated a rolling offensive on 18 October 1914, starting in Belgium, and extending the length of the western front. The primary focus of the attack was to amputate the Ypres salient, which protruded eastward between Steenstrat and St Eloi. At the northern end of the salient, there was cut and thrust between the combatants until a final German onslaught between 25–26 October. The Germans then deployed a purpose-built unit dedicated to breaching the British line on the southern salient round Gheluvelt. This came close to a decisive breakthrough and the Messines Ridge was taken, but with French reinforcements the Allied line held. A concluding engagement at Nonne Boschen on 11 November was indecisive at which point fighting petered out. The battle caused huge casualties in all the combatant armies, and convinced the German Chief of Staff, von Falkenhayn, that an offensive war on two fronts was unwinnable.