During the last six weeks of The Great War, the combined Allied troops were pushing the weakening German Army back through France towards Belgium. In one major attack in the Argonne Forest, about 550 American soldiers making up a battalion had little resistance in their sector of the line. It became so easy for them that they lost touch of their supporting flanks in the woods. The battalion, led by Major Charles Whittlesey, had one objective: to capture and hold Hill 198 at the Ravin de Charlevaux. They achieved their goal; problem was their mates on either side of them were under a German counter attack and stalled. The Germans realized a pocket of Americans were behind their lines and proceeded to surround them.
The Allied commanders at headquarters didn't realize the predicament, and for several days, those isolated soldiers were picked off one by one under constant firing. Their story was so inspiring that Hollywood produced a movie about them and their ordeal in July 1919's "The Lost Battalion." Its producers were able to get some survivors to re-enact their roles and secured the same knoll where the battle took place seven months before to film the battle scenes. "The Lost Battalion" is the first dramatic movie using actual participants to recreate a war event.
The movie set the standard of motion pictures about warfare by introducing several of the main characters beforehand. The viewer witnesses the personal stories of their home life and family members before they are sent to training camp. The second portion of "Lost Battalion" is the recreation of the battle, with occasional actual footage of World War One provided by the United States Signal Corps spliced in.
There's very little literary license involved in the structure of the film since the events were unique onto themselves. Once Major Whittlesey realized his forces were separated, he separately sent 24 runners to notify headquarters where they were. Not one made it. He also sent three carrier pigeons with messages giving his coordinates, but two were shot down by the Germans. The hero of the story was the third pigeon, named Cher Ami, who, despite being shot and wounded, was able to deliver its message. This was the first time the Allies realized a large group of their own men were surrounded under dire circumstances. Out of the 550 soldiers less than 200 came out physically unscathed.
A made-for-TV version by A&E of the WW1 event was produced in 2001 titled "The Lost Battalion." Needless to say, the modern film was unable to secure any of the actual soldiers who had been in the battle to reenact their roles, unlike the 1919 film.