The Germans turned their focus to Le Mort Homme on the west bank of the Meuse which blocked the route to French artillery emplacements, from which the French fired across the river. After some of the most intense fighting of the campaign, the hill was taken by the Germans in late May. After a change in French command at Verdun from the defensive-minded Philippe Pétain to the offensive-minded Robert Nivelle, the French attempted to re-capture Fort Douaumont on 22 May but were easily repulsed. The Germans captured Fort Vaux on 7 June and with the aid of diphosgene gas, came within of the last ridge before Verdun before being contained on 23 June.