title: Arlington National Cemetery
context: The national cemetery was established during the Civil War on the grounds of Arlington House, which had been the estate of Confederate general Robert E Lee's wife Mary Anna Custis Lee (a great-granddaughter of Martha Washington). The Cemetery, along with Arlington House, Memorial Drive, the Hemicycle, and the Arlington Memorial Bridge, form the Arlington National Cemetery Historic District, listed on the National Register of Historic Places in April 2014.[2][3]
question: When was Arlington National Cemetery first created?
answers: during the Civil War