A new PBS documentary will highlight the contributions of Bristol to country music. “Bristol – The Birthplace of Country Music” will premiere Saturday at the Paramount Center for the Arts. It’s the first in a series of eight roots-music shows produced for public television by “Mountain Stage,” the long-running live music show. In 1927, Ralph Peer arrived in Bristol where he recorded future Country Music Hall of Fame members Jimmie Rodgers, the Carter Family, the Stonemans and many others. Historians say the sessions marked the beginning of commercial country music. The show was filmed in Bristol last year. It will be available to stations nationwide later this month.