The Cheyennes were continuously hostile during the years 1855, 1856, and 1857, killing many whites and robbing numerous wagon-trains along the Platte River, which at that time was the great thoroughfare for travelers to Utah, California, Oregon, and other regions to the west of the Rocky Mountains. In 1857, the Cheyennes were severely punished in a number of engagements by troops under command of Colonel E. V. Sumner of the regular army, and as a result, they gave little trouble during the next five or six years. In the early days, the Arapahoes came in touch with the whites to a much greater extent than did the Cheyennes. The members of the latter tribe usually held aloof, and by their manner plainly expressed hatred of the white race. Horace Greeley, in his book describing his trip across the plains to California in 1859, tells of a large body of Arapahoes who were encamped on the outskirts of Denver in June of that year, because of the protection they thought it gave them from their enemies the Utes. I saw this band when I passed through Denver in June of the following year. The Sioux were one of the largest Indian nations upon the American continent. So far as is known, their original home was upon the Atlantic Coast in North Carolina, but by the time Europeans began to settle in that section they had drifted into the Western country. Their first contact with the white race occurred in the upper Mississippi region. These white people were the French explorers who had penetrated into almost every part of the interior long before the English had made any serious attempt at the exploration of the wilderness west of the Allegheny Mountains. The friendly relations between the French and the Sioux continued for many years, but when the French were finally supplanted by the English in most localities, the Sioux made an alliance with the latter which was maintained during the Revolutionary War, and continued until after the War of 1812. Subsequent to the year 1812, the Sioux gradually drifted still farther westward, and not many years later their principal home was upon the upper Missouri River. The recognized southern boundary of their country was the North Platte River, but on account of their friendly relations with the Cheyennes and Arapahoes, the Sioux often wandered along the base of the mountains as far as the Arkansas River, and, being at enmity with the Utes, they frequently joined the Cheyennes and Arapahoes in raids upon their common enemy.