Robert Edward Lee (January 19, 1807 – October 12, 1870) was a colonel in the United States Army. He became the General-in-chief of the Confederate States Army during the American Civil War. He led the Army of Northern Virginia in the Eastern Theater of the American Civil War. He started out as an engineer but then moved up the ranks. Before the Civil War, Lee was an officer in the Mexican-American War. He was also head of West Point. As a colonel in the United States Army he led a battalion of marines to put down the rebellion at Harpers Ferry Armory and captured their leader, John Brown.