During the First World War Verdun was a fortified French garrison town on the River Meuse 200km east of Paris. In December 1915, General Erich von Falkenhayn, Chief of Staff of the German Army, decided to attack Verdun. Although he admitted he would be unable to break through at these point on the Western Front, he argued that in defending Verdun, the Germans would "bleed the French army white". The German attack on Verdun started on 21st February 1916. A million troops, led by Crown Prince Wilhelm, faced only about 200,000 French defenders. The following day the French was forced to retreat to their second line of trenches. By 24th February the French had moved back to the third line and were only 8km from Verdun. On 24th February, General Henri-Philippe Petain was appointed commander of the Verdun sector. He gave orders that no more withdrawals would take place. He arranged for every spare French soldier to this part of the Western Front. Of the 330 infantry regiments of the French Army, 259 eventually fought at Verdun. The German advance was brought to a halt at the end of February. On the 6th March, the German Fifth Army launched a new attack at Verdun. The Germans advanced 3km before they were stopped in front of the area around Mort Homme Hill. The French held this strategic point until it was finally secured by the Germans on 29th May, and Fort Vaux fell on 7th June, after a long siege. Further attacks continued throughout the summer and early autumn. However, the scale of the German attacks were reduced by the need to transfer troops to defend their front-line at the Somme. The French now counter-attacked and General Charles Mangin became a national hero when the forts at Douaumont and Vaux were recaptured by 2nd November, 1916. Over the next six weeks the French infantry gained another 2km at Verdun. Verdun, the longest battle of the First World War, ended on the 18th December. The French Army lost about 550,000 men at Verdun. It is estimated that the German Army suffered 434,000 casualties. About half of all casualties at Verdun were killed.