Among the 17 National Guard divisions assigned to the American Expeditionary Force during World War I was the 28th Division, Pennsylvania National Guard. The 28th received its baptism of fire on July 15, 1918, during the German Army's Champagne-Marne Offensive. Four companies from the 28th were attached to a French division on the front line, while the rest of the division took up second-line defense positions. Two of the companies, L and M, were from the 109th Infantry Regiment made of the old 1st and 13th Pennsylvania Regiments. In the early hours of July 15, the German 36th Division crossed the Marne River and attacked the Allied front. When the adjacent French units fell back, L and M Companies were surrounded. Wave after wave of Germans attacked the Pennsylvanians. Despite the overwhelming odds, the two companies stubbornly held their position and inflicted heavy casualties. At 0800 the remnants of L and M Companies withdrew and fought their way back to the front line of the 109th, five kilometers away. Of the 500 assigned officers and men only 150 remained. The brunt of the German offensive now fell on the 109 Infantry and the other units of the 28th Division. For three days, the 109th held its positions while under heavy attack. Fighting in ravines, woods and trenches, the doughboys fought like veterans. A German after-action report described the battle as "the most severe defeat of the war." For its staunch defense the 109th was nicknamed "Men of Iron" and the 28th was later dubbed the "Iron Division." Today's 103d Engineer Battalion (The Dandy First) and the 109 Infantry (Thirteenth Pennsylvania) continue the proud heritage of the "Men of Iron."