This type of story is familiar (except the Jesuits don't adopt the Natives' way of life or beliefs, actually the opposite). So I would call this movie a "proto" Dances with Wolves, which other movies have derived from it, such as Pocahontas, Avatar, The Last Samurai.
shareA Man Called Horse is really the proto-Dances with Wolves.
shareIt's typically called a 'going native' story. Person from comparatively advances society goes back to a simpler way of life, realises that everything he thought he knew was wrong, and living off the land is the way to go.
Even when The Mission was first released, the idea was nothing new.
Never defend crap with 'It's just a movie'
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