At the start of the American Civil War, Whitman moved from New York to Washington, D.C., where he obtained work in a series of government offices, first with the Army Paymaster's Office and later with the Bureau of Indian Affairs. He volunteered in the army hospitals as a "hospital missionary." His wartime experiences informed his poetry which matured into reflections on death and youth, the brutality of war, patriotism, and offered stark images and vignettes of the war. Whitman's brother, George Washington Whitman, had been taken prisoner in Virginia on September 30, 1864 and was held for five months in Libby Prison, a Confederate prisoner-of-war camp near Richmond, Virginia. On February 24, 1865, George was granted a furlough to return home because of his poor health, and Whitman had travelled to his mother's home in New York to visit his brother. While visiting Brooklyn, Whitman contracted to have his collection of Civil War poems, "Drum-Taps", published.