Almost the only time that the pledge was broken was in the autumn of 1854. Continual trains of immigrants passing through the Sioux country made it nearly impossible to prevent friction between the races in which the blame was quite likely to fall upon the timorous homeseekers. On August 17, 1854, a cow strayed away from a band of Mormons encamped a few miles from Fort Laramie. Some have it that the cow was lame, and therefore abandoned; but whatever the cause, the cow was found, killed, and eaten by a small band of hungry Miniconjou Sioux. The charge of theft was brought into camp at Laramie, not by the Mormons, but by The Bear, chief of the Brulé, and Lieutenant Grattan with an escort of twenty-nine men, a twelve-pounder and a mountain howitzer, was sent out the next day to arrest the Indian who had slaughtered the animal. At the Indian village the culprit was not forthcoming, Grattan's drunken interpreter roughened a diplomacy which at best was none too tactful, and at last the troops fired into the lodge which was said to contain the offender. No one of the troops got away from the enraged Sioux, who, after their anger had led them to retaliate, followed it up by plundering the near-by post of the fur company. Commissioner Manypenny believed that this action by the troops was illegal and unnecessary from the start, since the Mormons could legally have been reimbursed from the Indian funds by the agent. No general war followed this outbreak. A few braves went on the war-path and rumors of great things reached the East, but General Harney, sent out with three regiments to end the Sioux war in 1855, found little opposition and fought only one important battle. On the Little Blue Water, in September, 1855, he fell upon Little Thunder's band of Brulé Sioux and killed or wounded nearly a hundred of them. There is some doubt whether this band had anything to do with the Grattan episode, or whether it was even at war, but the defeat was, as Agent Twiss described it, "a thunderclap to them." For the first time they learned the mighty power of the United States, and General Harney made good use of this object lesson in the peace council which he held with them in March, 1856. The treaty here agreed upon was never legalized, and remained only a sort of _modus vivendi_ for the following years. The Sioux tribes were so loosely organized that the authority of the chiefs had little weight; young braves did as they pleased regardless of engagements supposed to bind the tribes. But the lesson of the defeat lasted long in the memory of the plains tribes, so that they gave little trouble until the wars of 1864 broke out. Meanwhile Chouteau's old Fort Pierre on the Missouri was bought by the United States and made a military post for the control of these upper tribes.