Colonel Albert Sidney Johnston to Colonel Samuel Cooper, regarding the movement of troops under the leadership of Lt. Col. R.E. (Robert E.) Lee for the purpose of addressing Indian hostilities in western Texas, namely the Comanches under the command of Sa-na-co.
Albert Sidney Johnston commanded the 2nd Cavalry regiment in Texas at the time of this letter, though previously he had served as Secretary of War for the Republic of Texas and he would later die commanding his Confederate troops at the Battle of Shiloh in 1862.
Albert Sidney Johnston Letter, 1856, Center for American History, The University of Texas at Austin.