D.W. Griffith filmed some battle scenes during actual battles at the front in France. While he was out near the front trenches scouting locations, his party came under a surprise German artillery barrage. Griffith and his assistant jumped in a nearby ditch, and when the barrage was over they emerged from the ditch to discover that although they were uninjured, a shell had exploded near the ditch, killing the two soldiers acting as their escorts, along with a dozen other soldiers standing nearby.
The movie was commissioned by Great Britain, which hoped that a depiction of WWI would help spur the United States to join the allies. Although D.W. Griffith had the cooperation of the British, French and Belgian governments to film in their territories, his cameraman, G.W. Bitzer, was of German descent and was not allowed in France. Griffith used an army cameraman instead.
The Pennsylvania Board of Censors demanded that D.W. Griffith cut scenes of brutality from the film. Griffith's response to those demands was to cancel the Philadelphia opening.
D.W. Griffith (I) bought footage of the German army from an Austrian-American officer named Kleinschmit, who had been arrested in the US for espionage, and incorporated the footage into this film.