To-day we had a cold windy morning; the Black Cat [a Mandan chief] came to see us, and occupied us for a long time with questions on the usages [customs] of our country. He mentioned that a council had been held yesterday to deliberate on the state of their affairs. It seems that not long ago a party of Sioux fell in with some horses belonging to the Minnetarees and carried them off, but in their flight they were met by some Assiniboins, who killed the Sioux and kept the horses. A Frenchman, too, who had lived many years among the Mandans, was lately killed on his route to the British factory [trading post] on the Assiniboin…, all of which being discussed, the council decided that they would not resent the recent insults from the Assiniboins…until they had seen whether we had deceived them or not in our promises of furnishing them with arms and ammunition. They had been disappointed in their hopes of receiving them from Mr. Evans, and were afraid that we, too, like him, might tell them what was not true. We advised them to continue at peace, that supplies of every kind would no doubt arrive for them, but that time was necessary to organize the trade. The fact is that the Assiniboins treat the Mandans as the Sioux do the Ricaras; by their vicinity to the British they get all the supplies, which they withhold or give at pleasure to the remoter Indians; the consequence is that, however badly treated, the Mandans and Ricaras are very slow to retaliate lest they should lose their trade altogether.

Source: William Clark Journal, November 18, 1804, History of the Expeditions of Captains Lewis and Clark, 1804-5-6, Reprinted from the Edition of 1814, with Introduction and Index by James K. Hosmer (Chicago: A. C. McClurg, 1902), 1:136–37.