I read this short fiction (novelette or novella, not short story) more than 30 years ago, in a collection that was probably much older.
The main character is some kind of “Merchant Prince” but this has nothing to do with Asimov’s Foundation series, I just picked this name to describe him.
He has discovered an unknown planet inhabited by natives who are rather belligerent herders, depending also on hunting and gathering.
Still he starts to arrange some communication with one tribe for barter. But suddenly he is attacked and has to flee from his spaceship.
I am not sure whether a different tribe has attacked, but I think more probably that the first tribe suddenly changed from barter partners to enemies for some reason I do not remember.
He takes refuge in another tribe, because he needs help to recover his ship. IIRC, he tries to convince them that the tribe that has attacked him will steal their land with the powerful weapons they stole from his ship (which is a total lie). This starts something like a war.
But later he will stop the war, recover his ship and do (very profitable) barter not just with these two tribes but with many of the tribes on the planet.
Sam Azon most probably identified the "Merchant Prince" as Poul Anderson's character Nicholas Van Rijn.
But the are many stories about him, and IIRC, the two tribes I mention above belong to the same species of aliens. There is only one "sentient" species in my story. Different tribes, yes, but not different species, contrary to the case of "The Man Who Counts" which was initially proposed by Organic Marble, who then proposed the correct answer, namely "Territory".