Slave photo discovered from Robert E. Lee's home

The National Park Service has acquired a rare Civil War-era photograph of an enslaved woman who helped save Confederate Gen. Robert E. Lee's home in Arlington, Virginia.

The previously unknown photograph depicts Selina Gray, the head housekeeper to Lee and his family, along with two girls. The photograph was unveiled Thursday at the Arlington House plantation overlooking the nation's capital that was home to Lee and dozens of slaves before the Civil War.

An inscription on the back of the image reads "Gen Lees Slaves Arlington Va."