when did this genre of film originate?
In the early 20th century
War film
One of the earliest films using the Civil War as its subject was D.W. Griffith's 1910 silent picture, "The Fugitive".
what is wings (1927 film)? A 1927 American silent war film
wiki:19593103
War film [SEP] American Civil War
The costliest war in U.S. history in terms of American life, this war has been the subject of, or the backdrop to, numerous films, documentaries and mini-series. One of the earliest films using the Civil War as its subject was D.W. Griffith's 1910 silent picture, "The Fugitive". Films that have the war as its main subject, or about a certain aspect of the war include the 1989 film, "Glory", about the first formal unit of the Union Army during the American Civil War to be made up entirely of black men. Some films such as "Gettysburg" focused on a single battle during the war, or even on a single incident, like the French short film, "La Rivière du Hibou" ("An Occurrence at Owl Creek Bridge").