Other mistake: When Gregory Peck was being zoomed in on there are several fresh horse tracks.
Mackenna's Gold (1969)
1 other mistake
Directed by: J. Lee Thompson
Starring: Gregory Peck, Omar Sharif, Telly Savalas, Camilla Sparv
Continuity mistake: In the scene at The Yellow River where the Indians are chasing Gregory Peck and the gang of Omar Sharif on their way to the draft, you can see the same sequence with some trees (filmed with the camera holding up) twice within a second. (01:26:15)
Answer: Have to say, I have not seen movie, but to answer your question, one of the earliest surviving depictions of a person wearing sunglasses is of the scientist Antoine Lavoisier in 1772.
Triviani