I went down to the war fields in Virginia (end of 1862), lived thenceforward in camp⁠—saw great battles and the days and nights afterward⁠—partook of all the fluctuations, gloom, despair, hopes again arous’d, courage evoked⁠—death readily risk’d⁠— the cause , too⁠—along and filling those agonistic and lurid following years, 1863⁠–⁠’64⁠–⁠’65⁠—the real parturition years (more than 1776⁠–⁠’83) of this henceforth homogeneous Union. Without those three or four years and the experiences they gave, Leaves of Grass would not now be existing.