The First Battle of the Aisne () was the Allied follow-up offensive against the right wing of the German First Army (led by Alexander von Kluck) and the Second Army (led by Karl von Bülow) as they retreated after the First Battle of the Marne earlier in September 1914. The Advance to the Aisne (6 September – 1 October) consisted of the Battle of the Marne and the Battle of the Aisne The Battle 12–15 September When the Germans turned to face the pursuing Allies on 13 September, they held one of the most formidable positions on the Western Front. Between Compiègne and Berry-au-Bac, the Aisne River winds westward and is about wide, ranging from deep. Low-lying ground extends on each side, rising abruptly to a line of steep cliffs high, then gently levelling to a plateau. The Germans settled on the higher northern side beyond the crest, behind a dense thicket that covered the front and slope. Low crops in the unfenced countryside offered no natural concealment to the Allies. Deep, narrow paths cut into the escarpment at right angles, exposing any infiltrators to extreme hazard. The forces on the northern plateau commanded a wide field of fire. In dense fog on the night of 13 September, most of the British Expeditionary Force (BEF) crossed the Aisne on pontoons or partially demolished bridges, landing at Bourg-et-Comin on the right and at Venizel on the left. At Chivres-Val east of Venizel, there was an escarpment the Germans had selected as their strongest position. The French Fifth Army crossed the Aisne at Berry-au-Bac and captured the eastern tip of Chemin des Dames, a steep ridge named after the royal coach road Louis XV had built for his daughters. Contact was established along the entire front. East of Chemin des Dames, the French Fourth, Fifth and Ninth armies made only negligible progress beyond the positions they had reached on 13 September. Under the thick cover of the foggy night, the BEF advanced up the narrow paths to the plateau. When the mist evaporated under a bright morning sun, they were mercilessly raked by fire from the flank. Those caught in the valley without the fog's protective shroud fared no better. It soon became clear that neither side could budge the other and since neither chose to retreat, the impasse hardened into stalemate, that would lock the antagonists into a relatively narrow strip