The Sahaptian nations acquired horses through Northern Shoshone in the eighteenth century, radically changing their subsistence gathering patterns.
In 1841 Charles Wilkes stated that Piupiumaksmaks and Tawatoy were "going to the Shasta country to trade for blankets, powder and ball, together with trinkets and beads, in exchange for their horses and beaver-skins.
Regional trade was focused on Fort Nez Percés, a Hudson's Bay Company (HBC) post.
These transactions didn't include livestock as the HBC station maintained a policy of keeping its supply of animals.
Small numbers of ox and cattle were purchased from them, adding to the large horse herds already established.
Marcus Whitman reported to his superiors being lent two oxen from a Cayuse noble to establish Waiilaptu in 1836.
Several hundred head were brought back overland and distributed among its subscribers, ensuring their rising material progress.
The outfit contained a sizable number of members to ensure safety against potentially aggressive indigenous nations located between the Plateau and New Helvetia.
John Sutter welcomed the expedition to his colony, having become acquainted with Yellow Bird while he stayed at Fort Vancouver.
Stockpiles of Elk, Beaver and Deer furs were sold by the Salishan and Sahaptins for heads of cattle.
A clash of cultures occurred when the group returned to New Helvetia as the beasts of burden were formerly property of settlers there.
Mexican and American colonists demanded their return, offering initially ten and then fifteen cattle as recompense.
Yellow Bird and others did not find the offer valid as it was custom among Plateau natives for horses taken from enemies to become the property of new holders.
Several other Americans inside the building began to insult the group, with Cook stating "yesterday you was going to kill me, now you must die" to Toayahnu.
Spokane Garry narrowly avoided being shot, and the expedition was able to break out of New Helvetia without any additional losses.
As New Helvetia was located within Mexican Alta California, White held no authority there and was unable to compel any resolution to the conflict.
Another faction preferred to establish what the reactions of the HBC and Willamette Valley settlers to action against the California colonists.
A final block preferred military action against the California settlements as White recounted: He assured me that the Cayuse, Walla Wallas, Pend d'Oreilles, Flatheads, Nez Perces and Snakes, were all in terms of amity, and all that portion of the aggrieved party were for raising about two thousand warriors of these formidable tribes and march to California at once, and nobly revenge themselves on the inhabitants and then by plunder enrich themselves on the spoils.
A son of Piupiumaksmaks arrived several days in advance of the main party and informed his brethren the deaths caused from measles.