October 21, 1867, the group negotiated the Medicine Lodge Treaty with the tribes of the Southern plain. He and Gen. Sherman were the two commission members who finalized the Treaty of Bosque Redondo that was signed on June 1, 1868, at Fort Sumner, New Mexico, that ended the Bosque Redondo reservation fiasco. Tappan met several times with President Johnson and General Grant during his service with the commission, as well as many members of Congress. During his service with the commission, Tappan also recruited the young and inexperienced Henry Morton Stanley, later the famed African explorer and author, first as a clerk to cover the commission's work and later recommended that he be hired as a correspondent to file dispatches with major newspapers. Through this work, Stanley came to the attention of James Gordon Bennett, Jr. of the New York Herald, who later sent him to Africa in search of Dr. David Livingstone. Tappan also developed a lifelong friendship with the pioneer, buffalo hunter, Indian agent, illustrator and prominent Colorado artist/designer John Dare Howland, who was a clerk for the commission and later designed the Civil War monument at the Colorado Capitol building. Tappan also vociferously protested the Washita Massacre in November 1868 of Chief Black Kettle's Southern Cheyennes while camped near Ft. Sill Oklahoma Territory by Lt. Col. George A. Custer's Seventh Cavalry troopers. Tappan was also a leading member of Peter Cooper's United States Indian Commission, founded in 1869. He promoted legislation in favor of the funding of annuities and economic assistance promised to the Indians by the federal Indian Peace Commission two years before. Tappan remained active in the cause of native rights throughout the 1870s, strongly supporting President Ulysses S. Grant's peace policy. He openly charged that the efforts of the peace policy to reach a final settlement with Plains and Southwest Indians were being undermined by congressional railroad and land speculation interests, and that these interests were ultimately responsible for such atrocities against the Indians as the 1871 massacre of Eskiminzin's Apache band at Camp Grant, Arizona. Marriage and later life Following the Medicine Lodge Treaty in October 1867 which he attended as a Commissioner, Tappan adopted an orphaned Cheyenne girl whom he renamed Minnie Tappan. He made arrangements for Minnie to move back East to Boston, where she was enrolled in public school to further her education. After Tappan married the leading spiritualist Cora