On the 21st of September, 1805, he encamped on what is now known as Pike Island, at the junction of the Mississippi and Minnesota, then St. Peter's river. Two days later he obtained, by treaty with the Dakota nation, a tract of land for a military reservation, with the following boundaries, extending from "below the confluence of the Mississippi and St. Peter's, up the Mississippi, to include the Falls of St. Anthony, extending nine miles on each side of the river." The United States paid two thousand dollars for this land. The reserve thus purchased was not used for military purposes until Feb. 10, 1819, at which time the government gave the following reasons for erecting a fort at this point: "To cause the power of the United States government to be fully acknowledged by the Indians and settlers of the Northwest, to prevent Lord Selkirk, the Hudson Bay Company and others from establishing trading posts on United States territory, to better the conditions of the Indians, and to develop the resources of the country." Part of the Fifth United States Infantry, commanded by Colonel Henry Leavenworth, was dispatched to select a site and erect a post. They arrived at the St. Peter's river in September, 1819, and camped on or near the spot where now stands Mendota. During the winter of 1819-20 the troops were terribly afflicted with scurvy. General Sibley, in an address before the Minnesota Historical Society, in speaking of it, says: "So sudden was the attack that soldiers apparently in good health when they retired at night were found dead in the morning. One man who was relieved from his tour of sentinel duty, and had stretched himself upon a bench; when he was called four hours later to resume his duties, he was found lifeless." In May, 1820, the command left their cantonment, crossed the St. Peter's and went into summer camp at a spring near the old Baker trading house, and about two miles above the present site of Fort Snelling. This was called "Camp Coldwater." During the summer the men were busy in procuring logs and other material necessary for the work. The first site selected was where the present military cemetery stands, and the post was called "Fort St. Anthony;" but in August, 1820, Colonel Joshua Snelling of the Fifth United States Infantry arrived, and, on taking command, changed the site to where Fort Snelling now stands. Work steadily progressed until Sept. 10, 1820, when the corner stone of Fort St. Anthony was laid with all due ceremony. The first measured distance that was given between this new post and the next one down the river, Fort Crawford, where Prairie du Chien now stands, was 204 miles. The work was steadily pushed forward. The buildings were made of logs, and were first occupied in October, 1822. The first steamboat to arrive at the post was the "Virginia," in 1823.