Timothy H. O'Sullivan, American, b. Ireland?, 1840-1882 An important photographer of the American Civil War, <a href=" https://findartvalue.com/artist/timothy-h-osullivan">Timothy O'Sullivan</a> worked first for <a href=" https://findartvalue.com/artist/mathew-b-brady">Mathew Brady</a>, then <a href=" https://findartvalue.com/artist/alexander-gardner">Alexander Gardner</a> in their Washington, D.