This movie is a fictionalized account of how captives by the indigenous tribes generally were treated and ultimately acclimated to tribal life. The customs and practices depicted are not those of any specific tribe but provide only a generalized overview of tribal life in the North American indigenous culture. It is a good story in general and while not as "authentic" as was originally claimed when it first came out; personally I see it as more representative of tribal life than the more recent "Dances with Wolves". As with the more recent move, A Man Called Horse was assisted in production by members of various tribes with recreating the villages and tribal life depicted. Being a movie produced in the 70s, it did not make use of modern advances in cinematography, special effects, or CGI so in appearance it seems like an old movie. The net effect should be overlooked. It is a good story when viewed from a historical perspective with regard to the differences between tribal culture and colonial America.
I feel fortunate that this movie, along with its sequel, are still available on Blu-ray. Richard Harris (Sir Richard Harris) is one of my all time favorite actors. This is a great movie!