During an upcoming episode Ken Burns' Country Music, Rosanne Cash explains how "I Walk the Line" was written by her father Johnny Cash as a promise to her mother, Vivian Liberto, to overcome the carnal temptations of the road and honor his marriage vows. She punctuates the story behind the song with a bittersweet quip: "Of course that wasn't true."
Suspicions about her husband's bond with June Carter and frustrations over his addictions led Liberto to file for a divorce in 1966. Two years later, Johnny Cash married Carter -- an awkward circumstance that brought a strong role model into Rosanne's life.
"It seemed inevitable, though it was so painful for my mom," Rosanne tells People. "I had two really good examples from women in my life. My mom gave me this powerful sense of discipline, family, mothering and detail orientation. And June gave me this sense of expansiveness and how to live life as a performer."
Over time, Rosanne developed her own resentments toward a father occupied with wrestling personal demons and touring the globe. As Burns' series explains, those issues went to the wayside after the father and daughter duo sang "I Still Miss Someone" on stage during one of the Man in Black's tours.
"He worked out all his problems onstage, and that happened with me that night with him," Rosanne says to People. "It just all got fixed."
The extended Cash and Carter families play a huge role in Burns' eight episode, 16-and-a-half hour series, which debuted last night (Sept. 15). Episodes two through four air tonight through Wednesday on PBS, with the remaining episodes premiering next Sunday though Wednesday (Sept. 22-25).