The Battle of the Frontiers consisted of five offensives, commanded and planned by French Commander-in-Chief Joseph Joffre and German Chief-of-Staff Helmuth von Moltke. It was fought in August 1914. These five offensives, Mulhouse, Lorraine, Ardennes, Charleroi, and Mons, were launched almost simultaneously. They were the result of the French Plan XVII and the German plans colliding. The Battle of Mulhouse, on August 7–10, 1914, was envisioned by Joffre to anchor the French recapture of Alsace, but resulted in Joffre holding General Louis Bonneau responsible for its failure and replacing him with General Paul Pau. The Battle of Lorraine, August 14–25, was an indecisive French invasion of that region by General Pau and his Army of Alsace. The Battle of the Ardennes, fought between August 21 and 23 in the Ardennes forests, was sparked by unsuspecting French and German forces meeting, and resulted in a French defeat, forfeiting to the Germans a source of iron-ore. The Battle of Charleroi, which started on August 20 and ended on August 23, was a key battle on the Western Front, and a German victory. General Charles Lanrezac's retreat probably saved the French Army, but Joffre blamed him for the failure of Plan XVII, even though the withdrawal had been permitted.