American Military History, Volume 2 by Richard W. Stewart

To bleed off reserves from the north, on May 27 the German high command launched its third spring offensive at the French lines in the Chemin des Dames area northeast of Paris. By the end of the first day the attackers had driven the French over the Aisne River, the second defensive line. By the next day they were across the Vesle River and driving toward the Marne. When the offensive eventually ground to a halt, German troops were within fifty miles of Paris, almost as close as they had come in 1914.

The offensive had caught the Allies flatfooted. With most of the reserves in the north, Foch and Petain struggled to scrape up enough reserves to form a new line. To the west, the American 1st Division extended its lines to free a French division for redeployment. Moreover, two large American divisions (Maj. Gen. Omar Bundy's 2d Division and Maj. Gen. Joseph T. Dickman's 3d Division) entered the line near Château-Thierry on the Marne. Of the five American divisions almost ready for battle, Bundy's and Dickman's were closest to the path of the Germans. On May 30 they had been ordered forward to feed into the French line under French command.