Officials from NSU, Oklahoma Historical Society, Cherokee Nation and the Helmerich Center for American Research at the Gilcrease Museum gathered at the Oklahoma History Center on June 23 to commemorate the 150th anniversary of the end of the Civil War and to view facsimiles of several documents, including a three-page original signed copy of the treaty. Copies of the "Watie Treaty," a historical narrative by NSU professor Dr. Brad Agnew and other documents will be on display at the Oklahoma…