Question: What film, starring John Wayne, was one of the first major films based on the Vietnam War?
About the article "Vietnam War", section "Popular culture".

Candidate passages:
The Vietnam War has been the subject of many films.
One of the first major films based on the Vietnam War was John Wayne's "The Green Berets" (1968).
Further cinematic representations were released during the 1970s and 1980s, including Michael Cimino's "The Deer Hunter" (1978), Francis Ford Coppola's "Apocalypse Now" (1979), Oliver Stone's "Platoon" (1986) — based on his service in the U.S. Military during the Vietnam War, Stanley Kubrick's "Full Metal Jacket" (1987), "Hamburger Hill" (1987) and "Casualties of War" (1989).
Later films would include "We Were Soldiers" (2002) and "Rescue Dawn" (2007).
Other films in this genre include films that deal more with the issues veterans face at home after returning from the war.
Films of this type include "Taxi Driver" (1976), "Heroes" (1977), "Coming Home" (1978), "Combat Shock" (1986), "First Blood" (1982), "The War at Home" (1979), "Born on the Fourth of July" (1989), "Jacob's Ladder" (1990), "Heaven & Earth" (1993), "Forrest Gump" (1994), "Dead Presidents" (1995), and "Music Within" (2007). 
The book was adapted into a 1968 film of the same name starring John Wayne.
Production included extensive cooperation from the U.S. Army, which insisted that Moore not be involved with the film.
To please the Pentagon, Wayne bought Moore out for $35,000 and 5% of undefined profits of the film.
The movie version is noted for being one of the few films about Vietnam actually produced during the Vietnam War.
It is set in South Vietnam but was mostly filmed in and around Fort Benning. 
The Vietnam War has been featured extensively in television, film, video games, and literature in the participant countries.
In American popular culture, the "Crazy Vietnam Veteran", driven mad or otherwise disturbed by his experiences in Vietnam, became a common stock character after the war.
One of the first major films based on the Vietnam War was John Wayne's pro-war film, "The Green Berets" (1968).
Further cinematic representations were released during the 1970s and 1980s, including Michael Cimino's "The Deer Hunter" (1978), Francis Ford Coppola's "Apocalypse Now" (1979), Oliver Stone's "Platoon" (1986) — based on his service in the U.S. Military during the Vietnam War, Stanley Kubrick's "Full Metal Jacket" (1987), "Hamburger Hill" (1987), and "Casualties of War" (1989).
Later films would include "We Were Soldiers" (2002) and "Rescue Dawn" (2007).
The war also influenced a generation of musicians and songwriters in Vietnam and the United States, both anti-war and pro/anti-communist.
The band Country Joe and the Fish recorded "I-Feel-Like-I'm-Fixin'-To-Die Rag" / The "Fish" Cheer in 1965, and it became one of the most influential anti-Vietnam protest anthems.
Trinh Cong Son was a South Vietnamese songwriter famous for his anti-war songs.
The Shepherd of the Hills is a 1941 American drama film starring John Wayne, Betty Field and Harry Carey.
The supporting cast includes Beulah Bondi, Ward Bond, Marjorie Main and John Qualen.
The picture was Wayne's first film in Technicolor and was based on the novel of the same name by Harold Bell Wright.
The director was Henry Hathaway, who directed several other Wayne films including "True Grit" almost three decades later. 
John Wayne won a Best Actor Oscar for "True Grit" (1969).
Wayne was also nominated as the producer of Best Picture for "The Alamo" (1960), one of two films he directed.
The other was "The Green Berets" (1968), the only major film made during the Vietnam War to support the war.
During the filming of "Green Berets", the Degar or Montagnard people of Vietnam's Central Highlands, fierce fighters against communism, bestowed on Wayne a brass bracelet that he wore in the film and all subsequent films.
In an attempt to capitalize on the popularity of "Dirty Harry", Wayne took on the role of gritty detective "McQ" in the 1974 crime drama.
His last film was "The Shootist" (1976), whose main character, J.
B.
Books, was dying of cancer—the illness to which Wayne himself succumbed three years later.
According to the Internet Movie Database, Wayne played the lead in 142 of his film appearances.
Batjac, the production company co-founded by Wayne, was named after the fictional shipping company Batjak in "Wake of the Red Witch" (1948), a film based on the novel by Garland Roark.
(A spelling error by Wayne's secretary was allowed to stand, accounting for the variation.)
Batjac (and its predecessor, Wayne-Fellows Productions) was the arm through which Wayne produced many films for himself and other stars.
Its best-known non-Wayne production was the highly acclaimed "Seven Men From Now" (1956), which started the classic collaboration between director Budd Boetticher and star Randolph Scott.
In the "Motion Picture Herald" Top Ten Money-Making Western Stars poll, Wayne was listed in 1936 and 1939.
He appeared in the similar "Box Office" poll in 1939 and 1940.
While these two polls are really an indication only of the popularity of series stars, Wayne also appeared in the "Top Ten Money Makers Poll" of all films from 1949 to 1957 and 1958 to 1974, taking first place in 1950, 1951, 1954 and 1971.
With a total of 25 years on the list, Wayne has more appearances than any other star, beating Clint Eastwood (21) into second place.
In later years, Wayne was recognized as a sort of American natural resource, and his various critics, of his performances and his politics, viewed him with more respect.
Abbie Hoffman, the radical of the 1960s, paid tribute to Wayne's singularity, saying, "I like Wayne's wholeness, his style.
As for his politics, well—I suppose even cavemen felt a little admiration for the dinosaurs that were trying to gobble them up."
Reviewing "The Cowboys" (1972), Vincent Canby of the "New York Times", who did not particularly care for the film, wrote: "Wayne is, of course, marvelously indestructible, and he has become an almost perfect father figure."