As part of a general upheaval within the French government and military due in part to demoralizing losses at Verdun and the Somme, the formidable General Joseph-Jacques-CÉsaire Joffre is dismissed as commander in chief of the French forces in favor of General Robert Nivelle.
French authorities blamed Joffre, the stalwart champion of France s Plan XVII military strategy since 1911, for recent defeats on the Western Front as well as for the situation in the eastern Mediterranean, where some 500,000 Allied troops based out of the Greek port city of Salonika were mired in what they feared might be a losing struggle with Bulgarian forces. For his part, Nivelle believed an aggressive offensive was the key to a breakthrough on the Western Front. The French government felt pressure to take some action to counter the Germans declaration of unrestricted U-boat warfare; they were also swayed by the support Nivelle enjoyed from their counterparts in Britain, including the new prime minister, David Lloyd George.
In early April 1917, then, French and British troops embarked on what would become known as the Nivelle Offensive, hoping to quickly and decisively punch a hole through the German lines in France. All did not go as planned, however, as the strength and depth of the German positions, built up since the fall of 1914, proved too much for the Allies. By the end of the first day, almost all the French tanks, introduced into battle for the first time, had been destroyed or had become bogged down, and within a week the hospitals in the area were treating 96,000 wounded. The battle was called off on April 20.
The contrast between Nivelle s lofty objectives and the reality of the offensive s disappointing outcome caused great disillusionment and anger among the French troops. A series of mutinies began in late April 1917 and increased in the two succeeding months, eventually involving about 40,000 troops. Nivelle had cut soldiers leave time in March, only releasing 5 percent of the French army at a time. In July, Nivelle was replaced by Phillipe PÉtain, who increased the leave time given to each soldier to 13 percent, or ten days leave every four months, in an effort to curb discontent and offer the French troops some much-needed time to rest and recuperate.