German attempts to break through failed at the two battles of Ypres (1st/2nd) with huge casualties. A series of allied offensives in 1915 against German positions in Artois and Champagne resulted in huge allied casualties and little territorial change. German Chief of Staff Erich von Falkenhayn decided to exploit the defensive advantages that had shown themselves in the 1915 Allied offensives by attempting to goad France into attacking strong defensive positions near the ancient city of Verdun. Verdun had been one of the last cities to hold out against the German Army in 1870, and Falkenhayn predicted that as a matter of national pride the French would do anything to ensure that it was not taken. He expected that he could take strong defensive positions in the hills overlooking Verdun on the east bank of the River Meuse to threaten the city and the French would launch desperate attacks against these positions. He predicted that French losses would be greater than those of the Germans and that continued French commitment of troops to Verdun would "bleed the French Army white." In 1916, the Battle of Verdun began, with the French positions under constant shelling and poison gas attack and taking large casualties under the assault of overwhelmingly large German forces. However, Falkenhayn's prediction of a greater ratio of French killed proved to be wrong as both sides took heavy casualties. Falkenhayn was replaced by Erich Ludendorff, and with no success in sight, the German Army pulled out of Verdun in December 1916 and the battle ended.