On April 12, 1861, Confederate troops had fired on the federal garrison at Fort Sumter, South Carolina, prompting a number of states from the Deep South to join in rebellion. President Abraham Lincoln, newly installed in the White House, called up 75,000 troops to defend the capital. As the spring unfolded, the forces drifted into Washington, set up camp in the unfinished Capitol building, patrolled the city's thoroughfares and scrutinized the Virginia hills for signs of trouble. Although officially uncommitted to the Confederacy, Virginia was expected to join the revolt. When that happened, Union troops would have to take control of Arlington, where the heights offered a perfect platform for artillery—key to the defense or subjugation of the capital. Once the war began, Arlington was easily won. But then it became the prize in a legal and bureaucratic battle that would continue long after the guns fell silent at Appomattox in 1865. The federal government was still wrestling the Lee family for control of the property in 1882, by which time it had been transformed into Arlington National Cemetery, the nation's most hallowed ground.