By the time the fighting began again in May, Pétain had been promoted away from Verdun. He was replaced by General Robert Nivelle , who would later rise to command all the French armies. He inherited a much stronger position that Pétain had found in February. Eight French corps, containing over 500,000 men, faced eight German corps. The French had developed a process of revolving divisions into the line at Verdun for short periods of time, meaning that many of their men were fresh. In contrast very few German divisions were withdrawn from the battle, so by May many were made up of a mix of battle scarred veterans and new recruits.
Alfred von Schlieffen , German Army Chief of Staff, was given instructions to devise a strategy that would be able to counter a joint attack. In December, 1905, he began circulating what later became known as the Schlieffen Plan. Schlieffen argued that if war took place it was vital that France was speedily defeated. If this happened, Britain and Russia would be unwilling to carry on fighting. Schlieffen calculated that it would take Russia six weeks to organize its large army for an attack on Germany. Therefore, it was vitally important to force France to surrender before Russia was ready to use all its forces.
The General Staff of that time was a small, elite body, numbering as few as fifty and rarely exceeding one hundred officers. Only one or two officers were permanently assigned to the General Staff, described in official returns as des Generalstabs ("of the General Staff") at any time; most were attached to the General Staff while remaining affiliated to their parent regiments, usually for several years at a time, and were listed as im Generalstab ("on the General Staff"). When the General Staff was required to take the field during major campaigns, it remained a small but effective body. During the Franco-Prussian War for example, the staff that accompanied the headquarters of the King (as commander-in-chief) and was responsible for the direction of armies that totaled 850,000 men, consisted of the Chief of Staff, a Quartermaster-General and an Intendant-General whose duties were not directly concerned with military operations, three heads of departments, eleven other officers, ten draughtsmen, seven clerks and fifty-nine other ranks (orderlies, messengers etc.).