John Wayne nearly died twice during the filming of the 1969 Western The Undefeated, both times after being thrown by horses. Wayne had taken on the project with full creative control, surrounding himself with trusted collaborators, but the production was blighted by a pair of dangerous accidents that highlighted the physical risks he took even as one of Hollywood's most bankable stars.

In the first incident, a horse fell during filming and threw Wayne to the ground, leaving him with two broken ribs and forcing a short break from shooting while the crew filmed around him. Weeks later, after the cast regrouped in Baton Rouge, Louisiana, a loose stirrup caused him to fall from a horse mid-gallop and narrowly avoid being trampled, dislocating his shoulder. Wayne later reflected that he had been fortunate to escape with his life, recalling: "I fell right under the god-damned horse; I'm lucky I didn't kill myself."