A fierce battle took place at Stones River between December 31, 1862 and January 2, 1863. General Bragg's Confederates withdrew after the battle, allowing General Rosecrans and the Union army to control middle Tennessee. Although the battle was tactically indecisive, it provided a much-needed boost to the North after the defeat at Fredericksburg. Lincoln later wrote to General Rosecrans, "I can never forget [...] you gave us a hard-earned victory, which had there been a defeat instead, the nation could scarcely have lived over." The 600-acre National Battlefield includes Stones River National Cemetery, established in 1865, with more than 6,000 Union graves; and the Hazen Brigade Monument, believed to be the oldest, intact Civil War monument still standing in its original location. Portions of Fortress Rosecrans, a large earthen fort constructed after the battle, still stand and are preserved and interpreted by the National Park Service.