Some know Emmitt Smith as the National Football League's all-time leading rusher. Others recognize him as a three-time Super Bowl champion or a Dancing with the Stars winner.

But do you really know who Emmitt is?

Until he traced his genealogy for the NBC reality series "Who Do You Think You Are?", Emmitt says he didn't even know the answer to that question.

Emmitt soon learned that his great-great-grandmother, Victoria, had an unusual maiden name -- Puryear.

Genealogist Marjorie Sholes told Emmitt that "Puryear" was probably the name of a slave owner. "African-Americans, at the end of the Civil War, sometimes picked the names of their last slave owner," she says.