Beginning about 1800, these two federated tribes, accompanied by some of the Sioux, with whom they had made peace, gradually moved southward along the eastern base of the Rocky Mountains. Dr. James, the historian of Long's expedition which visited the Pike's Peak region in 1820, mentions the fact that about four years previous there had been a large encampment of Indians on a stream near Platte Cañon, southwest of Denver, which had assembled for trading purposes. It appears that the Cheyennes had been supplied with goods by British traders on the Missouri River, and had met to exchange these goods for horses. The tribes dwelling on the fertile plains of the Arkansas and Red rivers always had a great number of horses, which they reared with much less difficulty than did the Cheyennes, who usually spent the winter in the country farther to the north, where the cold weather lasted much longer and feed was less abundant. After many years of warfare with the Kiowas, the Cheyennes and Arapahoes were victorious, and by a treaty, made in 1840, secured undisputed possession of the territory north of the Arkansas River and east of the mountains. As this was only eighteen years before the coming of the whites, the Cheyennes and Arapahoes could not rightfully claim this region as their ancestral home. The country acquired by the Cheyennes and Arapahoes, through their victory over the Kiowas, embraced a territory of more than eighty thousand square miles. As in those two tribes there were never more than five thousand men, women, and children, all told, the area was out of all proportion to their numbers. Early in 1861, the Government made a treaty with the Cheyennes and Arapahoes by which these tribes gave up the greater part of the lands claimed by them in the new Territory of Colorado. For this they were to receive a consideration of four hundred and fifty thousand dollars, to be paid in fifteen yearly installments, the tribes reserving for their own use a tract about seventy miles square located on both sides of the Arkansas River in the southeastern part of the Territory. From the time of their first contact with the whites, the Cheyennes and Arapahoes were alternately friendly or hostile, just as their temper or whim dictated upon any particular occasion. With the old trappers and hunters of the plains, the Cheyennes had the reputation of being the most treacherous and untrustworthy at all times and in all places, of any of the tribes of the West. The Arapahoes, while occasionally committing depredations against the whites, were said to be somewhat different in temperament, in that they were not so sullen and morose as the Cheyennes, and were less treacherous and more open and trustworthy in their dealings. This estimate of the characteristics of the two tribes was fully confirmed in our contact with them in the early days of Colorado.