the Crater, suffering over 4,000 casualties. The battle was portrayed in the film Cold Mountain (2003). By the end of the war, the city was ringed with a series of fortifications. In early April 1865, Union troops finally managed to push their left flank to the railroad to Weldon, North Carolina and the Southside Railroad. With the loss of Petersburg's crucial lifelines, the Confederate forces had to retreat, ending the siege in a victory for the Union Army. The fall of Petersburg meant that Richmond could no longer be defended, Lee attempted to lead his men south to join up with Confederate forces in North Carolina. Hopelessly outnumbered, he was surrounded and forced to surrender at Appomattox Court House, Virginia, on April 9, 1865. Confederate General Ambrose P. (A.P.) Hill died on the last day the Confederates held the Petersburg trenches. Petersburg established a warfare precedent. During World War I the armies on both sides used trenches extensively in Europe (q.v. trench warfare). Reconstruction era The Freedmen's Bureau established new facilities for freedmen, including a mental health hospital in December 1869, at Howard's Grove Hospital, a former Confederate unit. In 1870 the General Assembly incorporated the Central Lunatic Asylum as an organized state institution, as part of an effort by the Reconstruction-era legislature to increase public institutions for general welfare. The legislature also founded the state's first system of free public education. In the years after the Civil War, many freedmen migrated to Petersburg for rebuilding, work on the river, and to escape the white control prevalent in more rural areas. They found numerous churches, businesses and institutions founded by free blacks, and added new energy to the community. In 1874 James M. Wilkerson Sr. founded the Wilkerson Undertaking Company. It continues to operate as the James M. Wilkerson Funeral Establishment, Inc. and is one of the oldest black-owned firms in the United States. Although in the 1870s, conservative whites took power in the state and began to legislate racial segregation, African Americans continued to create their own businesses and community organizations in Petersburg. During the 1880s, a coalition of black Republicans and white Populists held power for several years in the state legislature. This resulted in two major public institutions in Petersburg, as the legislature invested in education and welfare. In 1882, the legislature founded Virginia State University in nearby Ettrick as Virginia Normal and Collegiate Institute. It was