At midnight on Sunday, 14th July, Paris was awakened by the sound of great guns, and knew that the battle had begun. At 4 a.m. on the 15th the Germans crossed their parapets. The thrust beyond the Marne was at once successful, for it was no part of Foch's plan to resist too doggedly at the apex of the salient. On a front of 22 miles the Germans advanced nearly three. But the attack east of Rheims was an utter failure. Gouraud's counter-bombardment dislocated the attack before it began, and with trifling losses to himself he held the advance in his battle zone, not losing a single gun. In the west the Americans stood firm, so that the enemy salient could not be widened. These were the troops which, according to the German belief, could not land in Europe unless they became fishes or birds. The inconceivable had been brought to pass--"Birnam Wood had come to Dunsinane."
In two days the German advance had reached its limit--a long narrow salient south of the Marne, representing a progress at the most of 6 miles from the old battle-front. The time had now come for Foch's counterstroke. He had resolved to thrust with all his available reserves against the weak enemy flank from Soissons southward. There, in the shelter of the woods of Villers-Cotterets, lay the army of Mangin, who first won fame at Verdun.
The morning of the 18th dawned after a night of thunderstorms and furious winds. There was no gunfire on the French side, but at 4.30, out from the shelter of the woods came a great fleet of French light tanks, and behind them on a front of 35 miles the French and American infantry crossed the parapets. Before the puzzled enemy could realize his danger they were through his first defences.
The advance of the 18th was like a great bound forward. The chief work was done by Mangin's left wing, which at half-past 10 in the morning held the crown of the Montagne de Paris, on the edge of Soissons. All down the line the Allies succeeded. Sixteen thousand prisoners fell to them and some 50 guns, and at one point Mangin had advanced as much as 8 miles. Foch had narrowed the German salient, crumpled its western flank, and destroyed its communications. He had wrested the initiative from the Germans and brought their last offensive to a dismal close.