On Thursday evening, backstage in a dressing room at Nashville’s Ryman Auditorium, Peter Rowan is plucking his guitar and quietly humming to himself. With less than an hour before showtime, the singer-songwriter will soon celebrate a band he created more than a half-century ago, one whose influence continues to loom large over bluegrass music — Old & In the Way.

“A lot of people who’ve picked up on Old & In the Way have gone deeper into the Stanley Brothers, Lonesome Pine Fiddlers, Bill Monroe,” the 82-year-old tells Rolling Stone. “They follow the trail.