During the Sixties and Seventies, John Wayne was riddled with ailing well being. 

The hard-drinking, chain-smoking star had a cancerous lung eliminated again in 1964 and would secretly depend on an oxygen masks on film units, particularly if at excessive altitudes.

By 1973, he was 65 and filming certainly one of his final Westerns, Cahill US Marshall, however was affected by emphysema on his single lung.

Being considerably weakened, Wayne was compelled to make use of a stepladder to climb onto his horse within the film.

As for using photographs from a distance, Duke’s Cahill needed to be doubled by Chuck Roberson.