Where are the Cheyenne prophesies of Sweet Medicine recorded?

Question

The American Buffalo, a recent documentary film series by Ken Burns, includes several quotations that it attributes to a Cheyenne prophet called Sweet Medicine.

Regarding European settlers:

There is a time coming. Many things will change. Strangers will appear among you. Their skins are light-colored, and their ways are powerful. These people do not follow the way of our great-grandfather. They follow another way. [...]

These strangers will be a people who do not get tired, but who will keep pushing forward, going, going all the time. They will keep coming, coming. Follow nothing that they do, but keep your own ways that I have taught you as long as you can.

Regarding the horse:

There will be an animal you must learn to use. It has a shaggy neck and a tail almost touching the ground. Its hooves are round. This animal will carry you on his back and help you in many ways. Those far hills that seem only a blue vision in the distance take many days to reach now, but with this animal, you can get there in a short time, so fear it not. Remember what I have said.

While the film initially left me with the impression that Sweet Medicine was a known historical person from the period of initial European contact, the paucity of sources I'm seeing online leads me to think that he is more of a legendary figure or cultural hero known only from oral tradition. The Wikipedia article on the Cheyenne people simply states (apparently without relevant links or citations):

Sweet Medicine is the Cheyenne prophet who predicted the coming of the horse, the cow, the white man and other new things to the Cheyenne. He was named for motsé'eonȯtse (sweetgrass), one of the sacred plant medicines used by many Plains peoples in ceremonies.

So how exactly are these prophecies known to us today? Is it primarily from the oral traditions of living Cheyenne people? Or are there written sources (perhaps old ethnography) that the film might be quoting from?

Answer 1

It looks like Sweet Medicine (Motsé'eóeve) is sort of a legendary cultural hero/founder/prophet figure for the Cheyenne. Sort of like their Romulus.

From what I've been able to gather, it looks like what we have written from Sweet Medicine is largely ultimately sourced from a series of recordings made by anthropologist Margot Liberty with Cheyenne tribal historian John Stands in Timber in the 1950's. Stands in Timber had earlier in his life talked with as many elders as he could, to learn all the Cheyenne oral histories he possibly could.

I'm not sure where one would go to get hold of the raw recordings (this claims to be a complete transcription), but they did publish a book based on those recordings in 1967 named Cheyenne Memories.

I see hints of other works about Sweet Medicine, but it seems likely any information they contain was ultimately sourced from there, and any that isn't I'd worry about being contaminated by Euro-American influence, or just flat out made up.

Answer 2

It seems that the earliest mention of SWEET MEDICINE made in a book comes from the work of George Bird Grinnell in his 1926 book "By Cheyenne Campfires"

https://www.worldhistory.org/article/2355/the-life-and-death-of-sweet-medicine/