The third effort to make contact with these Western Indians was successfully carried out in 1834, by what became known as the famous Dragoon Expedition. General Henry Leavenworth arrived at Fort Gibson April 28 of that year and assumed command of the post, which he held until June 12 when he departed in command of the expedition. This expedition included also Colonel Henry Dodge, Colonel Stephen Watts Kearney, and Major R. B. Mason. Jefferson Davis, a lieutenant a few years out of West Point, was in command of one company. This train of five hundred mounted troops, a large number of white-covered baggage wagons, and seventy head of beeves made an imposing procession. It was accompanied by eleven Osage, eight Cherokee, six Delaware, and seven Seneca Indians who went along to serve as guides, hunters, interpreters, and as representatives of their respective nations. They crossed the Arkansas River below the mouth of Grand River, passed over the prairies near the site of the future Muskogee, traveled southwest to the mouth of the Washita River, then northwest, where they visited the site of a Comanche village at the western end of the Wichita Mountains. This was a disastrous expedition which resulted in the deaths of nearly 150 men from disease and the effects of excessive hot weather and poor water upon the unseasoned and undisciplined soldiers lately recruited from private life in the North and East. Included among the casualties of this expedition was that of General Leavenworth, who died July 21 near the Washita River. However, they did succeed in bringing back to Fort Gibson representatives of the Kiowa, Wichita, and Waco tribes, and after their return invitations were extended to all the Indians within reach to attend a grand council at the post—Choctaws, Cherokees, Creeks, Senecas, Osages, Delawares, and others. Here, on September 2, 1834, began one of the most interesting and important Indian councils ever held in the country. On this occasion every effort was made to impress the wild Indians who had never made a treaty with the United States and make them understand the changed political condition of the country. There were 150 Indians participating in the council, and with their numerous women and children, tepees and tents, they made one of the most picturesque scenes ever witnessed at any army post. Governor Stokes and the army officers who attended did not have authority at this time to enter into a treaty, but, with the potent influence of Colonel A. P. Chouteau, who participated in the council, the commissioners secured an agreement with the wild Indians to meet in treaty council the following year. And so the plans which were launched and carried out at Fort Gibson resulted in a treaty council begun August 24, 1835, at Fort Mason on the Canadian River near the present Purcell, Oklahoma, where was negotiated the first treaty ever entered into by a number of these western tribes.